CVE detail
CVE-2026-11525
Impact: When undici parses a Set-Cookie header, it accepts any SameSite attribute value that contains Strict, Lax, or None as a substring, rather than the case-insensitive exact match specified by RFC 6265. Non-spec values are silently mapped to one of the three standard tokens. For example, SameSite=NoneOfYourBusiness is parsed as None (the most permissive setting), and SameSite=StrictLax is parsed as Lax (a downgrade from Strict). Affected applications are those that consume Set-Cookie headers from server responses (for example via undici's fetch or proxy code paths) and then forward or rely on the parsed sameSite attribute. A malicious or non-compliant server can coerce the consumer's view of a cookie's SameSite policy to a weaker value, silently degrading the SameSite enforcement the cookie is supposed to provide. This was introduced in undici 5.15.0 when the cookies feature was added. Patches: Upgrade to undici v6.26.0, v7.28.0 or v8.5.0. Workarounds: After parsing a Set-Cookie header, validate that the resulting sameSite attribute is one of 'Strict', 'Lax', or 'None' (exact, case-insensitive) before forwarding or relying on it.
Buzz score
Why this CVE is surfacing
This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.
Buzz score components · mention 13.9 · diversity 15.0 · KEV 0.0 · OTX 0.0 · PoC 0.0
Why it matters now
Mention timeline
- Total mentions
- 0
- within the 30d window
- Peak daily
- 0
- highest bucket
Evidence
Source links by recency
3 source links · newest first
- CVE-2026-11525 undici vulnerable to Set-Cookie SameSite attribute downgrade via permissive substring matchingMicrosoft MSRC
Information published.
vendormsrc.microsoft.comJun 28, 2026, 9:00 AM No excerpt available.
Exploitgithub.comJun 17, 2026, 6:17 PM- https://cna.openjsf.org/security-advisories.htmlcna.openjsf.org
No excerpt available.
Vendor Advisorycna.openjsf.orgJun 17, 2026, 6:17 PM
Exploit code
Public exploit repository references
Public PoC repositories are third-party, potentially unsafe artifacts. Treat their code as untrusted and use it only on authorized systems in an isolated, least-privilege environment. cvebuzz does not execute the code or verify that an exploit works.
0 repository references · best confidence N/A · max 0 stars
Related records
Similar CVEs
6 related CVEs with shared weakness or product evidence
- CVE-2026-67345CVSS 8.5 · High
MaxKey through 4.1.12, fixed in commit ddbb72f, contains an insufficient redirect URI validation vulnerability in DefaultRedirectResolver.hostMatches() that allows remote attacker…
- CVE-2026-66005CVSS 5.3 · Medium
Jan through 0.8.4, fixed in commit 3e1c1e7, contains a CORS misconfiguration vulnerability in its local API server that allows network-adjacent attackers to bypass trusted host re…
- CVE-2026-16129CVSS 1.9 · Low
A vulnerability has been found in princezuda SafestClaw up to 4.2.4. This vulnerability affects the function ShellAction._validate_command of the file src/safestclaw/actions/shell…
- CVE-2026-46341CVSS 6.1 · Medium
The Apify MCP server enables AI agents to extract data from websites using ready-made scrapers, crawlers, and automation tools available on the Apify Store. Prior to 0.9.21, the f…
- CVE-2026-15625CVSS 2.1 · Low
A vulnerability was found in nextlevelbuilder GoClaw 3.11.3. Affected by this issue is the function ExecApprovalManager.CheckCommand of the file internal/tools/exec_approval.go. T…
- CVE-2026-59802CVSS 6.3 · Medium
PasswordPusher before 2.8.1 accepts data URI schemes in URL push payloads due to insufficient validation in the valid_url function. Attackers can create malicious pushes containin…