@angular/common: XSRF Token Leakage via URL Parsing Discrepancy in Angular HTTP Client (Incomplete fix for CVE-2025-66035) · CVE-2026-111753 · GitHub Advisory Database · GitHub
Skip to content

@angular/common: XSRF Token Leakage via URL Parsing Discrepancy in Angular HTTP Client (Incomplete fix for CVE-2025-66035)

Moderate severity GitHub Reviewed Published Oct 16, 2026 in angular/angular • Updated Oct 20, 2026

Package

npm @angular/common (npm)

Affected versions

>= 21.0.0, < 21.0.3
>= 20.0.0, < 20.3.34
<= 19.2.25

Patched versions

21.0.3
20.3.34

Description

An incomplete fix for GHSA-58c5-g7wp-6w37 (CVE-2025-66035) in @angular/common's HTTP Client (HttpClient) allows Cross-Site Request Forgery (XSRF) tokens to be leaked to attacker-controlled cross-origin domains when requests use URLs that exploit parsing discrepancies between regular expressions and the browser's WHATWG URL parser.

Technical Description

To address CVE-2025-66035, xsrfInterceptorFn introduced a regular expression (const ABSOLUTE_URL_REGEX = /^(?:https?:)?\/\//i) to detect and skip absolute and protocol-relative URLs before attaching the X-XSRF-TOKEN header.

However, browsers resolve request URLs passed to fetch() and XMLHttpRequest.open() using the WHATWG URL parser. For http: and https: schemes, the WHATWG URL standard performs several normalizations prior to resolving the authority/origin:

  • Backslashes (\) are treated as forward slashes (/) — e.g., /\evil.example/x, \\evil.example/x, \/evil.example/x, https:\\evil.example/x, https:/\evil.example/x.
  • Leading and trailing C0 control characters and spaces (<= 0x20) are stripped — e.g., ' //evil.example/x', '\0//evil.example/x', '\x1f//evil.example/x'.
  • ASCII tab (\t), newline (\n), and carriage return (\r) characters are removed anywhere in the input — e.g., '/\t/evil.example/x', '/\n/evil.example/x', 'htt\tps://evil.example/x'.

Because these URLs do not match /^(?:https?:)?\/\//i, xsrfInterceptorFn treats them as relative same-origin URLs and attaches the X-XSRF-TOKEN header, while the browser resolves and dispatches the request to the cross-origin host (evil.example).

Note: Angular 21.0.3+ and 22.x replaced the regular expression with a WHATWG new URL(req.url, locationOrigin) origin comparison in #65683 and were already unaffected. However, the 20.3.x LTS branch retained the regular expression until 20.3.34.

Impact

The token leakage bypasses Angular's built-in XSRF protection on affected versions, allowing an attacker to capture the user's valid X-XSRF-TOKEN header if their server permits the request and custom header via CORS. Once obtained, the attacker can perform Cross-Site Request Forgery (CSRF) attacks against the victim user's session.

Attack Preconditions

  1. The victim's Angular application must have XSRF protection enabled (enabled by default in HttpClient).
  2. The attacker must be able to make the application send a state-changing HTTP request (e.g., POST, PUT, DELETE, PATCH) to a URL they control (such as /\attacker.example/api or //attacker.example/api).

Patches

The issue is resolved by parsing and comparing the request URL's origin against the application's current origin using the standard URL constructor (new URL(req.url, locationOrigin)).

  • 21.0.3 (and all 22.x releases)
  • 20.3.34

Workarounds

If you cannot immediately upgrade to a patched version:

  • Validate and normalize outgoing request URLs using new URL(url, window.location.origin) and verify that parsedUrl.origin === window.location.origin before passing dynamic URLs to mutating HttpClient requests.
  • Avoid passing untrusted or user-controlled URLs to HttpClient mutating methods.

References

@alan-agius4 alan-agius4 published to angular/angular Oct 16, 2026
Published to the GitHub Advisory Database Oct 20, 2026
Reviewed Oct 20, 2026
Last updated Oct 20, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements Present
Privileges Required None
User interaction Active
Vulnerable System Impact Metrics
Confidentiality High
Integrity None
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

EPSS score

Weaknesses

Insertion of Sensitive Information Into Sent Data

The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor. Learn more on MITRE.

Exposure of Private Personal Information to an Unauthorized Actor

The product does not properly prevent a person's private, personal information from being accessed by actors who either (1) are not explicitly authorized to access the information or (2) do not have the implicit consent of the person about whom the information is collected. Learn more on MITRE.

CVE ID

CVE-2026-111753

GHSA ID

GHSA-jfgx-762w-99vr

Source code

Credits

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.