undici vulnerable to Set-Cookie SameSite attribute downgrade via permissive substring matching
CVE-2026-11525 is a vulnerability in undici version 3.0 related to the handling of the Set-Cookie SameSite attribute. The issue involves a permissive substring matching that can lead to a downgrade of the SameSite attribute, potentially weakening cookie security. No CVSS score or detailed impact information is provided. There is no indication of known exploits in the wild or available patches at this time.
AI Analysis
Technical Summary
The vulnerability identified as CVE-2026-11525 affects undici version 3.0 and involves a flaw in the processing of the Set-Cookie SameSite attribute. Specifically, permissive substring matching allows the attribute to be downgraded, which may reduce the intended security protections of the SameSite cookie attribute. This vulnerability is categorized under CWE-183 (Incorrect Regular Expression). No patch or remediation details are currently provided by the vendor, and no exploits are known in the wild.
Potential Impact
The impact of this vulnerability is a potential weakening of cookie security controls by downgrading the SameSite attribute, which could affect the enforcement of cookie policies designed to prevent cross-site request forgery and related attacks. However, no specific exploitation details or confirmed impacts are documented.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch information is available, monitor the Microsoft Security Response Center for updates. No specific mitigation steps are provided by the vendor at this time.
undici vulnerable to Set-Cookie SameSite attribute downgrade via permissive substring matching
Description
CVE-2026-11525 is a vulnerability in undici version 3.0 related to the handling of the Set-Cookie SameSite attribute. The issue involves a permissive substring matching that can lead to a downgrade of the SameSite attribute, potentially weakening cookie security. No CVSS score or detailed impact information is provided. There is no indication of known exploits in the wild or available patches at this time.
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability identified as CVE-2026-11525 affects undici version 3.0 and involves a flaw in the processing of the Set-Cookie SameSite attribute. Specifically, permissive substring matching allows the attribute to be downgraded, which may reduce the intended security protections of the SameSite cookie attribute. This vulnerability is categorized under CWE-183 (Incorrect Regular Expression). No patch or remediation details are currently provided by the vendor, and no exploits are known in the wild.
Potential Impact
The impact of this vulnerability is a potential weakening of cookie security controls by downgrading the SameSite attribute, which could affect the enforcement of cookie policies designed to prevent cross-site request forgery and related attacks. However, no specific exploitation details or confirmed impacts are documented.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch information is available, monitor the Microsoft Security Response Center for updates. No specific mitigation steps are provided by the vendor at this time.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_vex
- Csaf Version
- 2.0
- Publisher
- Microsoft Security Response Center
- Advisory Id
- msrc_CVE-2026-11525
- Cve Count
- 1
- Additional Cves
- []
- Cvss Version
- null
Threat ID: 6a535c3968715ace43adfef8
Added to database: 07/12/2026, 09:19:53 UTC
Last enriched: 07/12/2026, 09:32:32 UTC
Last updated: 07/12/2026, 10:19:44 UTC
Views: 5
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