CWE - CWE-1275: Sensitive Cookie with Improper SameSite Attribute (4.20)
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    CWE-1275: Sensitive Cookie with Improper SameSite Attribute

    Weakness ID: 1275
    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.
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    + Description
    The SameSite attribute for sensitive cookies is not set, or an insecure value is used.
    + Extended Description
    The SameSite attribute controls how cookies are sent for cross-domain requests. This attribute may have three values: 'Lax', 'Strict', or 'None'. If the 'None' value is used, a website may create a cross-domain POST HTTP request to another website, and the browser automatically adds cookies to this request. This may lead to Cross-Site-Request-Forgery (CSRF) attacks if there are no additional protections in place (such as Anti-CSRF tokens).
    + Common Consequences
    Section HelpThis 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

    Modify Application Data

    		Scope: Confidentiality, Integrity, Non-Repudiation, Access Control

    Likelihood: Low
    If the website does not impose additional defense against CSRF attacks, failing to use the 'Lax' or 'Strict' values could increase the risk of exposure to CSRF attacks. The likelihood of the integrity breach is Low because a successful attack does not only depend on an insecure SameSite attribute. In order to perform a CSRF attack there are many conditions that must be met, such as the lack of CSRF tokens, no confirmations for sensitive actions on the website, a "simple" "Content-Type" header in the HTTP request and many more.
    + Potential Mitigations
    Phase(s) Mitigation

    Implementation
    Set the SameSite attribute of a sensitive cookie to 'Lax' or 'Strict'. This instructs the browser to apply this cookie only to same-domain requests, which provides a good Defense in Depth against CSRF attacks. When the 'Lax' value is in use, cookies are also sent for top-level cross-domain navigation via HTTP GET, HEAD, OPTIONS, and TRACE methods, but not for other HTTP methods that are more like to cause side-effects of state mutation.

    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 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. 923 Improper Restriction of Communication Channel to Intended Endpoints
    CanPrecede Composite Composite - a Compound Element that consists of two or more distinct weaknesses, in which all weaknesses must be present at the same time in order for a potential vulnerability to arise. Removing any of the weaknesses eliminates or sharply reduces the risk. One weakness, X, can be "broken down" into component weaknesses Y and Z. There can be cases in which one weakness might not be essential to a composite, but changes the nature of the composite when it becomes a vulnerability. 352 Cross-Site Request Forgery (CSRF)
    + Modes Of Introduction
    Section HelpThe 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 This weakness occurs during implementation when the coder does not properly set the SameSite attribute.
    + Applicable Platforms
    Section HelpThis 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)

    Operating Systems

    Class: Not OS-Specific (Undetermined Prevalence)

    Architectures

    Class: Not Architecture-Specific (Undetermined Prevalence)

    Technologies

    Class: Web Based (Undetermined Prevalence)

    Web Server (Undetermined Prevalence)

    + Likelihood Of Exploit
    Medium
    + 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 snippet of code below establishes a new cookie to hold the sessionID.

    (bad code)
    Example Language: JavaScript 
    let sessionId = generateSessionId()
    let cookieOptions = { domain: 'example.com' }
    response.cookie('sessionid', sessionId, cookieOptions)

    Since the sameSite attribute is not specified, the cookie will be sent to the website with each request made by the client. An attacker can potentially perform a CSRF attack by using the following malicious page:

    (attack code)
    Example Language: HTML 
    <html>
    <form id=evil action="http://local:3002/setEmail" method="POST">
    <input type="hidden" name="newEmail" value="abc@example.com" />
    </form>
    <script>evil.submit()</script>
    </html>

    When the client visits this malicious web page, it submits a '/setEmail' POST HTTP request to the vulnerable website. Since the browser automatically appends the 'sessionid' cookie to the request, the website automatically performs a 'setEmail' action on behalf of the client.

    To mitigate the risk, use the sameSite attribute of the 'sessionid' cookie set to 'Strict'.

    (good code)
    Example Language: JavaScript 
    let sessionId = generateSessionId()
    let cookieOptions = { domain: 'example.com', sameSite: 'Strict' }
    response.cookie('sessionid', sessionId, cookieOptions)


    + 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
    Web application for a room automation system has client-side JavaScript that sets a sensitive cookie without the SameSite security attribute, allowing the cookie to be sniffed
    + 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
    + Memberships
    Section HelpThis 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.
    Nature Type ID Name
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1345 OWASP Top Ten 2021 Category A01:2021 - Broken Access Control
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1396 Comprehensive Categorization: Access Control
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1436 OWASP Top Ten 2025 Category A01:2025 - Broken Access Control
    + 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
    [REF-1104] M. West and M. Goodwin. "SameSite attribute specification draft". 2016-04-06.
    <https://datatracker.ietf.org/doc/html/draft-west-first-party-cookies-07>. (URL validated: 2023-04-07)
    [REF-1105] Mozilla. "SameSite attribute description on MDN Web Docs". 2020-06-20.
    <https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Set-Cookie#samesitesamesite-value>. (URL validated: 2025-08-04)
    [REF-1106] The Chromium Projects. "Chromium support for SameSite attribute". 2019-09-26.
    <https://www.chromium.org/updates/same-site/>. (URL validated: 2023-04-07)
    + Content History
    + Submissions
    Submission Date Submitter Organization
    2020-06-19
    (CWE 4.1, 2020-02-24)     		Michael Stepankin Veracode
    + Modifications
    Modification Date Modifier Organization
    2025-12-11
    (CWE 4.19, 2025-12-11)     		CWE Content Team MITRE
    updated Applicable_Platforms, Relationships, Weakness_Ordinalities
    2025-09-09
    (CWE 4.18, 2025-09-09)     		CWE Content Team MITRE
    updated References
    2023-10-26
    (CWE 4.13, 2023-10-26)     		CWE Content Team MITRE
    updated Demonstrative_Examples, Observed_Examples
    2023-06-29
    (CWE 4.12, 2023-06-29)     		CWE Content Team MITRE
    updated Mapping_Notes
    2023-04-27
    (CWE 4.11, 2023-04-27)     		CWE Content Team MITRE
    updated Detection_Factors, References, Relationships
    2023-01-31
    (CWE 4.10, 2023-01-31)     		CWE Content Team MITRE
    updated Relationships
    2022-10-13
    (CWE 4.9, 2022-10-13)     		CWE Content Team MITRE
    updated Demonstrative_Examples
    2021-10-28
    (CWE 4.6, 2021-10-28)     		CWE Content Team MITRE
    updated Relationships
    2020-08-20
    (CWE 4.2, 2020-08-20)     		CWE Content Team MITRE
    updated Demonstrative_Examples, Related_Attack_Patterns
    Page Last Updated: April 30, 2026