CVE-2026-11525
LOWCVSS v3.1: 3.7 · EPSS: 0.0025 (15.9 percentile)
Source data as of:
At a glance
- Severity
- LOW
- CVSS
- 3.7 v3.1 · NVD
- EPSS
- 0.0025 (15.9 percentile) · FIRST.org
- CISA KEV
- No
- Attack conditions (CVSS vector)
- NetworkNo privilegesNo user interaction · Source: NVD Vector
- Affected vendors
- nodejs
- Published
- 2026-06-17 · Modified: 2026-06-25
- References
- Jump to references (2)
CVSS / EPSS / KEV
Source — CVSS: NVD · EPSS: FIRST.org · KEV: CISA. Data & Sources
Description
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.
References
Reference URLs as listed by NVD, grouped by a mechanical match on the link's host/pattern. Labels describe the link type only.
- Vendor advisory https://cna.openjsf.org/security-advisories.html
- Vendor advisory https://github.com/nodejs/undici/security/advisories/GHSA-g8m3-5g58-fq7m