[v5] git: Add strict checks for supported extensions by pjbgf · Pull Request #1861 · go-git/go-git

@pjbgf

The upstream Git enforces fail-safe heuristics to ensure that older git versions
will avoid handling repositories using extensions they are unaware of.

The logic is largely based on the value of core.repositoryformatversion. As per
official Git docs:
> This version specifies the rules for operating on the on-disk repository data.
> An implementation of git which does not understand a particular version
> advertised by an on-disk repository MUST NOT operate on that repository;
> doing so risks not only producing wrong results, but actually losing data.

Now go-git will ensure that:
- The git.Open logic will verify and enforces the extension support rules.
- go-git will keep track of built-in extensions that it supports.

This is a breaking change and it will force go-git to not be able to open
repositories that it in fact doesn't really support. Conversaly, the error
messages will be more useful (e.g. unknown extension vs object not found).

Upstream refs:
- https://git-scm.com/docs/git-config#Documentation/git-config.txt-extensions
- https://git-scm.com/docs/gitrepository-layout#_git_repository_format_versions

Signed-off-by: Paulo Gomes <pjbgf@linux.com>

@pjbgf marked this pull request as ready for review

February 24, 2026 12:08

Copilot AI review requested due to automatic review settings

February 24, 2026 12:08

@pjbgf

The test workflow for v5 diverged from main slightly, including its
job name, which caused it to not be in-sync with the latest repository
rulesets.

Signed-off-by: Paulo Gomes <pjbgf@linux.com>

@pjbgf pjbgf deleted the backport-checks branch

February 24, 2026 12:35

arthurzam pushed a commit to gentoo-golang-dist/forgejo-runner that referenced this pull request

Feb 27, 2026

Maks1mS pushed a commit to stplr-dev/stplr that referenced this pull request

Feb 28, 2026
This PR contains the following updates:

| Package | Type | Update | Change | OpenSSF |
|---|---|---|---|---|
| [github.com/go-git/go-git/v5](https://github.com/go-git/go-git) | require | minor | `v5.16.5` → `v5.17.0` | [![OpenSSF Scorecard](https://api.securityscorecards.dev/projects/github.com/go-git/go-git/badge)](https://securityscorecards.dev/viewer/?uri=github.com/go-git/go-git) |

---

> ⚠️ **Warning**
>
> Some dependencies could not be looked up. Check the Dependency Dashboard for more information.

---

### Release Notes

<details>
<summary>go-git/go-git (github.com/go-git/go-git/v5)</summary>

### [`v5.17.0`](https://github.com/go-git/go-git/releases/tag/v5.17.0)

[Compare Source](go-git/go-git@v5.16.5...v5.17.0)

#### What's Changed

- build: Update module github.com/go-git/go-git/v5 to v5.16.5 \[SECURITY] (releases/v5.x) by [@&#8203;go-git-renovate](https://github.com/go-git-renovate)\[bot] in [#&#8203;1839](go-git/go-git#1839)
- git: worktree, optimize infiles function for very large repos by [@&#8203;k-anshul](https://github.com/k-anshul) in [#&#8203;1853](go-git/go-git#1853)
- git: Add strict checks for supported extensions by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1861](go-git/go-git#1861)
- backport, git: Improve Status() speed with new index.ModTime check by [@&#8203;cedric-appdirect](https://github.com/cedric-appdirect) in [#&#8203;1862](go-git/go-git#1862)
- storage: filesystem, Avoid overwriting loose obj files by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1864](go-git/go-git#1864)

**Full Changelog**: <go-git/go-git@v5.16.5...v5.17.0>

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At 12:00 AM through 04:59 AM and 10:00 PM through 11:59 PM, Monday through Friday ( * 0-4,22-23 * * 1-5 ), Only on Sunday and Saturday ( * * * * 0,6 ) (UTC), Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

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 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My4xNS4yIiwidXBkYXRlZEluVmVyIjoiNDMuMTUuMiIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOlsiS2luZC9EZXBlbmRlbmNpZXMiXX0=-->

Reviewed-on: https://altlinux.space/stapler/stplr/pulls/333
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charithe added a commit to charithe/cerbos that referenced this pull request

Mar 9, 2026
v5.17.0 includes strict extension checks (go-git/go-git#1861) but it
causes problems for `worktreeconfig` because it wasn't added to the
supported extension list until go-git/go-git#1877. Until it's released,
we need to keep the version back.

Signed-off-by: Charith Ellawala <charith@cerbos.dev>

charithe added a commit to cerbos/cerbos that referenced this pull request

Mar 9, 2026
v5.17.0 includes strict extension checks (go-git/go-git#1861) but it
causes problems for `worktreeconfig` because it wasn't added to the
supported extension list until go-git/go-git#1877. Until it's released,
we need to keep the version back.

Signed-off-by: Charith Ellawala <charith@cerbos.dev>

Signed-off-by: Charith Ellawala <charith@cerbos.dev>

haines pushed a commit to haines/cerbos that referenced this pull request

Mar 16, 2026
v5.17.0 includes strict extension checks (go-git/go-git#1861) but it
causes problems for `worktreeconfig` because it wasn't added to the
supported extension list until go-git/go-git#1877. Until it's released,
we need to keep the version back.

Signed-off-by: Charith Ellawala <charith@cerbos.dev>

migmartri added a commit to migmartri/chainloop that referenced this pull request

Mar 30, 2026
go-git v5.17.0 introduced strict repository extension validation
(go-git/go-git#1861) with a case-sensitivity bug that rejects the
worktreeConfig extension, breaking attestation init in repos using
git worktree.

Reverts to v5.16.5 and adds defensive handling in gracefulGitRepoHead
so unsupported extension errors degrade gracefully instead of failing
the attestation.

Closes chainloop-dev#2966

Signed-off-by: Miguel Martinez Trivino <miguel@chainloop.dev>

This was referenced

Mar 30, 2026

nschloe pushed a commit to live-clones/forgejo that referenced this pull request

Mar 31, 2026
…0/forgejo) (#11898)

This PR contains the following updates:

| Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|
| [github.com/go-git/go-git/v5](https://github.com/go-git/go-git) | `v5.16.5` → `v5.17.1` | ![age](https://developer.mend.io/api/mc/badges/age/go/github.com%2fgo-git%2fgo-git%2fv5/v5.17.1?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/go/github.com%2fgo-git%2fgo-git%2fv5/v5.16.5/v5.17.1?slim=true) |

---

> ⚠️ **Warning**
>
> Some dependencies could not be looked up. Check the [Dependency Dashboard](issues/2779) for more information.

---

### go-git missing validation decoding Index v4 files leads to panic
[CVE-2026-33762](https://nvd.nist.gov/vuln/detail/CVE-2026-33762) / [GHSA-gm2x-2g9h-ccm8](GHSA-gm2x-2g9h-ccm8)

<details>
<summary>More information</summary>

#### Details
##### Impact

`go-git`’s index decoder for format version 4 fails to validate the path name prefix length before applying it to the previously decoded path name. A maliciously crafted index file can trigger an out-of-bounds slice operation, resulting in a runtime panic during normal index parsing.

This issue only affects Git index format version 4. Earlier formats (`go-git` supports only `v2` and `v3`) are not vulnerable to this issue.

An attacker able to supply a crafted `.git/index` file can cause applications using go-git to panic while reading the index. If the application does not recover from panics, this results in process termination, leading to a denial-of-service (DoS) condition.

Exploitation requires the ability to modify or inject a Git index file within the local repository in disk. This typically implies write access to the `.git` directory.

##### Patches

Users should upgrade to `v5.17.1`, or the latest `v6` [pseudo-version](https://go.dev/ref/mod#pseudo-versions), in order to mitigate this vulnerability.

##### Credit

go-git maintainers thank @&#8203;kq5y for finding and reporting this issue privately to the `go-git` project.

#### Severity
- CVSS Score: 2.8 / 10 (Low)
- Vector String: `CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L`

#### References
- [https://github.com/go-git/go-git/security/advisories/GHSA-gm2x-2g9h-ccm8](https://github.com/go-git/go-git/security/advisories/GHSA-gm2x-2g9h-ccm8)
- [https://github.com/go-git/go-git](https://github.com/go-git/go-git)

This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-gm2x-2g9h-ccm8) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)).
</details>

---

### go-git: Maliciously crafted idx file can cause asymmetric memory consumption
[CVE-2026-34165](https://nvd.nist.gov/vuln/detail/CVE-2026-34165) / [GHSA-jhf3-xxhw-2wpp](GHSA-jhf3-xxhw-2wpp)

<details>
<summary>More information</summary>

#### Details
##### Impact

A vulnerability has been identified in which a maliciously crafted `.idx` file can cause asymmetric memory consumption, potentially exhausting available memory and resulting in a Denial of Service (DoS) condition.

Exploitation requires write access to the local repository's `.git` directory, it order to create or alter existing `.idx` files.

##### Patches

Users should upgrade to `v5.17.1`, or the latest `v6` [pseudo-version](https://go.dev/ref/mod#pseudo-versions), in order to mitigate this vulnerability.

##### Credit

The go-git maintainers thank @&#8203;kq5y for finding and reporting this issue privately to the `go-git` project.

#### Severity
- CVSS Score: 5.0 / 10 (Medium)
- Vector String: `CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H`

#### References
- [https://github.com/go-git/go-git/security/advisories/GHSA-jhf3-xxhw-2wpp](https://github.com/go-git/go-git/security/advisories/GHSA-jhf3-xxhw-2wpp)
- [https://github.com/go-git/go-git](https://github.com/go-git/go-git)
- [https://github.com/go-git/go-git/releases/tag/v5.17.1](https://github.com/go-git/go-git/releases/tag/v5.17.1)

This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-jhf3-xxhw-2wpp) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)).
</details>

---

### Release Notes

<details>
<summary>go-git/go-git (github.com/go-git/go-git/v5)</summary>

### [`v5.17.1`](https://github.com/go-git/go-git/releases/tag/v5.17.1)

[Compare Source](go-git/go-git@v5.17.0...v5.17.1)

#### What's Changed

- build: Update module github.com/cloudflare/circl to v1.6.3 \[SECURITY] (releases/v5.x) by [@&#8203;go-git-renovate](https://github.com/go-git-renovate)\[bot] in [#&#8203;1930](go-git/go-git#1930)
- \[v5] plumbing: format/index, Improve v4 entry name validation by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1935](go-git/go-git#1935)
- \[v5] plumbing: format/idxfile, Fix version and fanout checks by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1937](go-git/go-git#1937)

**Full Changelog**: <go-git/go-git@v5.17.0...v5.17.1>

### [`v5.17.0`](https://github.com/go-git/go-git/releases/tag/v5.17.0)

[Compare Source](go-git/go-git@v5.16.5...v5.17.0)

#### What's Changed

- build: Update module github.com/go-git/go-git/v5 to v5.16.5 \[SECURITY] (releases/v5.x) by [@&#8203;go-git-renovate](https://github.com/go-git-renovate)\[bot] in [#&#8203;1839](go-git/go-git#1839)
- git: worktree, optimize infiles function for very large repos by [@&#8203;k-anshul](https://github.com/k-anshul) in [#&#8203;1853](go-git/go-git#1853)
- git: Add strict checks for supported extensions by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1861](go-git/go-git#1861)
- backport, git: Improve Status() speed with new index.ModTime check by [@&#8203;cedric-appdirect](https://github.com/cedric-appdirect) in [#&#8203;1862](go-git/go-git#1862)
- storage: filesystem, Avoid overwriting loose obj files by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1864](go-git/go-git#1864)

**Full Changelog**: <go-git/go-git@v5.16.5...v5.17.0>

</details>

---

### Configuration

📅 **Schedule**: Branch creation - "" (UTC), Automerge - Between 12:00 AM and 03:59 AM ( * 0-3 * * * ) (UTC).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My45OS4xIiwidXBkYXRlZEluVmVyIjoiNDMuOTkuMSIsInRhcmdldEJyYW5jaCI6InYxMS4wL2Zvcmdlam8iLCJsYWJlbHMiOlsiZGVwZW5kZW5jeS11cGdyYWRlIiwidGVzdC9ub3QtbmVlZGVkIl19-->

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11898
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>
Co-authored-by: Renovate Bot <bot@kriese.eu>
Co-committed-by: Renovate Bot <bot@kriese.eu>

nschloe pushed a commit to live-clones/forgejo that referenced this pull request

Mar 31, 2026
…v14.0/forgejo) (#11899)

This PR contains the following updates:

| Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|
| [github.com/go-git/go-git/v5](https://github.com/go-git/go-git) | `v5.16.5` → `v5.17.1` | ![age](https://developer.mend.io/api/mc/badges/age/go/github.com%2fgo-git%2fgo-git%2fv5/v5.17.1?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/go/github.com%2fgo-git%2fgo-git%2fv5/v5.16.5/v5.17.1?slim=true) |

---

### go-git missing validation decoding Index v4 files leads to panic
[CVE-2026-33762](https://nvd.nist.gov/vuln/detail/CVE-2026-33762) / [GHSA-gm2x-2g9h-ccm8](GHSA-gm2x-2g9h-ccm8)

<details>
<summary>More information</summary>

#### Details
##### Impact

`go-git`’s index decoder for format version 4 fails to validate the path name prefix length before applying it to the previously decoded path name. A maliciously crafted index file can trigger an out-of-bounds slice operation, resulting in a runtime panic during normal index parsing.

This issue only affects Git index format version 4. Earlier formats (`go-git` supports only `v2` and `v3`) are not vulnerable to this issue.

An attacker able to supply a crafted `.git/index` file can cause applications using go-git to panic while reading the index. If the application does not recover from panics, this results in process termination, leading to a denial-of-service (DoS) condition.

Exploitation requires the ability to modify or inject a Git index file within the local repository in disk. This typically implies write access to the `.git` directory.

##### Patches

Users should upgrade to `v5.17.1`, or the latest `v6` [pseudo-version](https://go.dev/ref/mod#pseudo-versions), in order to mitigate this vulnerability.

##### Credit

go-git maintainers thank @&#8203;kq5y for finding and reporting this issue privately to the `go-git` project.

#### Severity
- CVSS Score: 2.8 / 10 (Low)
- Vector String: `CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L`

#### References
- [https://github.com/go-git/go-git/security/advisories/GHSA-gm2x-2g9h-ccm8](https://github.com/go-git/go-git/security/advisories/GHSA-gm2x-2g9h-ccm8)
- [https://github.com/go-git/go-git](https://github.com/go-git/go-git)

This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-gm2x-2g9h-ccm8) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)).
</details>

---

### go-git: Maliciously crafted idx file can cause asymmetric memory consumption
[CVE-2026-34165](https://nvd.nist.gov/vuln/detail/CVE-2026-34165) / [GHSA-jhf3-xxhw-2wpp](GHSA-jhf3-xxhw-2wpp)

<details>
<summary>More information</summary>

#### Details
##### Impact

A vulnerability has been identified in which a maliciously crafted `.idx` file can cause asymmetric memory consumption, potentially exhausting available memory and resulting in a Denial of Service (DoS) condition.

Exploitation requires write access to the local repository's `.git` directory, it order to create or alter existing `.idx` files.

##### Patches

Users should upgrade to `v5.17.1`, or the latest `v6` [pseudo-version](https://go.dev/ref/mod#pseudo-versions), in order to mitigate this vulnerability.

##### Credit

The go-git maintainers thank @&#8203;kq5y for finding and reporting this issue privately to the `go-git` project.

#### Severity
- CVSS Score: 5.0 / 10 (Medium)
- Vector String: `CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H`

#### References
- [https://github.com/go-git/go-git/security/advisories/GHSA-jhf3-xxhw-2wpp](https://github.com/go-git/go-git/security/advisories/GHSA-jhf3-xxhw-2wpp)
- [https://github.com/go-git/go-git](https://github.com/go-git/go-git)
- [https://github.com/go-git/go-git/releases/tag/v5.17.1](https://github.com/go-git/go-git/releases/tag/v5.17.1)

This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-jhf3-xxhw-2wpp) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)).
</details>

---

### Release Notes

<details>
<summary>go-git/go-git (github.com/go-git/go-git/v5)</summary>

### [`v5.17.1`](https://github.com/go-git/go-git/releases/tag/v5.17.1)

[Compare Source](go-git/go-git@v5.17.0...v5.17.1)

#### What's Changed

- build: Update module github.com/cloudflare/circl to v1.6.3 \[SECURITY] (releases/v5.x) by [@&#8203;go-git-renovate](https://github.com/go-git-renovate)\[bot] in [#&#8203;1930](go-git/go-git#1930)
- \[v5] plumbing: format/index, Improve v4 entry name validation by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1935](go-git/go-git#1935)
- \[v5] plumbing: format/idxfile, Fix version and fanout checks by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1937](go-git/go-git#1937)

**Full Changelog**: <go-git/go-git@v5.17.0...v5.17.1>

### [`v5.17.0`](https://github.com/go-git/go-git/releases/tag/v5.17.0)

[Compare Source](go-git/go-git@v5.16.5...v5.17.0)

#### What's Changed

- build: Update module github.com/go-git/go-git/v5 to v5.16.5 \[SECURITY] (releases/v5.x) by [@&#8203;go-git-renovate](https://github.com/go-git-renovate)\[bot] in [#&#8203;1839](go-git/go-git#1839)
- git: worktree, optimize infiles function for very large repos by [@&#8203;k-anshul](https://github.com/k-anshul) in [#&#8203;1853](go-git/go-git#1853)
- git: Add strict checks for supported extensions by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1861](go-git/go-git#1861)
- backport, git: Improve Status() speed with new index.ModTime check by [@&#8203;cedric-appdirect](https://github.com/cedric-appdirect) in [#&#8203;1862](go-git/go-git#1862)
- storage: filesystem, Avoid overwriting loose obj files by [@&#8203;pjbgf](https://github.com/pjbgf) in [#&#8203;1864](go-git/go-git#1864)

**Full Changelog**: <go-git/go-git@v5.16.5...v5.17.0>

</details>

---

### Configuration

📅 **Schedule**: Branch creation - "" (UTC), Automerge - Between 12:00 AM and 03:59 AM ( * 0-3 * * * ) (UTC).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My45OS4xIiwidXBkYXRlZEluVmVyIjoiNDMuOTkuMSIsInRhcmdldEJyYW5jaCI6InYxNC4wL2Zvcmdlam8iLCJsYWJlbHMiOlsiZGVwZW5kZW5jeS11cGdyYWRlIiwidGVzdC9ub3QtbmVlZGVkIl19-->

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11899
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>
Co-authored-by: Renovate Bot <bot@kriese.eu>
Co-committed-by: Renovate Bot <bot@kriese.eu>