Vulnerabilities fixed

Sourced from The GitHub Security Advisory Database.

Moderate severity vulnerability that affects puma

Keepalive thread overload/DoS

Impact

A poorly-behaved client could use keepalive requests to monopolize Puma's reactor and create a denial of service attack.

If more keepalive connections to Puma are opened than there are threads available, additional connections will wait permanently if the attacker sends requests frequently enough.

Patches

This vulnerability is patched in Puma 4.3.1 and 3.12.2.

Workarounds

Reverse proxies in front of Puma could be configured to always allow less than X keepalive connections to a Puma cluster or process, where X is the number of threads configured in Puma's thread pool.

For more information

If you have any questions or comments about this advisory:

... (truncated)

Affected versions: < 3.12.2

Sourced from The Ruby Advisory Database.

Keepalive thread overload/DoS in puma A poorly-behaved client could use keepalive requests to monopolize Puma's reactor and create a denial of service attack.

If more keepalive connections to Puma are opened than there are threads available, additional connections will wait permanently if the attacker sends requests frequently enough.

Patched versions: ~> 3.12.2; >= 4.3.1 Unaffected versions: none

Sourced from The GitHub Security Advisory Database.

Moderate severity vulnerability that affects puma In Puma (RubyGem) before 4.3.2 and 3.12.2, if an application using Puma allows untrusted input in a response header, an attacker can use newline characters (i.e. CR, LF or/r, /n) to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as HTTP Response Splitting.

While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS).

This is related to CVE-2019-16254, which fixed this vulnerability for the WEBrick Ruby web server.

This has been fixed in versions 4.3.2 and 3.12.3 by checking all headers for line endings and rejecting headers with those characters.

Affected versions: < 3.12.3

Sourced from The Ruby Advisory Database.

HTTP Response Splitting vulnerability in puma If an application using Puma allows untrusted input in a response header, an attacker can use newline characters (i.e. CR, LF) to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as HTTP Response Splitting.

While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS).

Patched versions: ~> 3.12.4; >= 4.3.3 Unaffected versions: none

Sourced from The GitHub Security Advisory Database.

Moderate severity vulnerability that affects puma

Impact

If an application using Puma allows untrusted input in an early-hints header, an attacker can use a carriage return character to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as HTTP Response Splitting

While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS).

This is related to CVE-2020-5247, which fixed this vulnerability but only for regular responses.

Patches

This has been fixed in 4.3.3 and 3.12.4.

Workarounds

Users can not allow untrusted/user input in the Early Hints response header.

For more information

If you have any questions or comments about this advisory:

• Open an issue in puma
• Email us a project maintainer. Email addresses are listed in our Code of Conduct.

Affected versions: < 3.12.4

Sourced from The GitHub Security Advisory Database.

HTTP Smuggling via Transfer-Encoding Header in Puma

Impact

This is a similar but different vulnerability to the one patched in 3.12.5 and 4.3.4.

A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client.

If the proxy uses persistent connections and the client adds another request in via HTTP pipelining, the proxy may mistake it as the first request's body. Puma, however, would see it as two requests, and when processing the second request, send back a response that the proxy does not expect. If the proxy has reused the persistent connection to Puma to send another request for a different client, the second response from the first client will be sent to the second client.

Patches

The problem has been fixed in Puma 3.12.6 and Puma 4.3.5.

For more information

If you have any questions or comments about this advisory:

• Open an issue in Puma
• See our security policy

Affected versions: < 3.12.6

Sourced from The GitHub Security Advisory Database.

HTTP Smuggling via Transfer-Encoding Header in Puma

Impact

By using an invalid transfer-encoding header, an attacker could smuggle an HTTP response.

Originally reported by @​ZeddYu, who has our thanks for the detailed report.

Patches

The problem has been fixed in Puma 3.12.5 and Puma 4.3.4.

For more information

If you have any questions or comments about this advisory:

• Open an issue in Puma
• See our security policy

Affected versions: < 3.12.5

Sourced from The Ruby Advisory Database.

HTTP Smuggling via Transfer-Encoding Header in Puma

Impact

By using an invalid transfer-encoding header, an attacker could smuggle an HTTP response.

Patches

The problem has been fixed in Puma 3.12.5 and Puma 4.3.4.

Patched versions: ~> 3.12.5; >= 4.3.4 Unaffected versions: none

Sourced from The Ruby Advisory Database.

HTTP Smuggling via Transfer-Encoding Header in Puma

Impact

This is a similar but different vulnerability to the one patched in 3.12.5 and 4.3.4.

A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client.

If the proxy uses persistent connections and the client adds another request in via HTTP pipelining, the proxy may mistake it as the first request's body. Puma, however, would see it as two requests, and when processing the second request, send back a response that the proxy does not expect. If the proxy has reused the persistent connection to Puma to send another request for a different client, the second response from the first client will be sent to the second client.

Patches

The problem has been fixed in Puma 3.12.6 and Puma 4.3.5.

Patched versions: ~> 3.12.6; >= 4.3.5 Unaffected versions: none

Sourced from The Ruby Advisory Database.

HTTP Response Splitting (Early Hints) in Puma

Impact

If an application using Puma allows untrusted input in an early-hints header, an attacker can use a carriage return character to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as HTTP Response Splitting

While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS).

This is related to CVE-2020-5247, which fixed this vulnerability but only for regular responses.

Patches

This has been fixed in 4.3.3 and 3.12.4.

Workarounds

Users can not allow untrusted/user input in the Early Hints response header.

Patched versions: ~> 3.12.4; >= 4.3.3 Unaffected versions: none

Sourced from The Ruby Advisory Database.

HTTP Response Splitting vulnerability in puma If an application using Puma allows untrusted input in a response header, an attacker can use newline characters (i.e. CR, LF) to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as HTTP Response Splitting.

While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS).

Patched versions: ~> 3.12.4; >= 4.3.3 Unaffected versions: none

Sourced from The GitHub Security Advisory Database.

Keepalive Connections Causing Denial Of Service in puma This vulnerability is related to CVE-2019-16770.

Impact

The fix for CVE-2019-16770 was incomplete. The original fix only protected existing connections that had already been accepted from having their requests starved by greedy persistent-connections saturating all threads in the same process. However, new connections may still be starved by greedy persistent-connections saturating all threads in all processes in the cluster.

A puma server which received more concurrent keep-alive connections than the server had threads in its threadpool would service only a subset of connections, denying service to the unserved connections.

Patches

This problem has been fixed in puma 4.3.8 and 5.3.1.

Workarounds

Setting queue_requests false also fixes the issue. This is not advised when using puma without a reverse proxy, such as nginx or apache, because you will open yourself to slow client attacks (e.g. slowloris).

The fix is very small. A git patch is available here for those using unsupported versions of Puma.

For more information

... (truncated)

Affected versions: <= 4.3.7