cvedb.io
CVE-2026-9679
MEDIUM · CVSS 5.9
EPSS exploitation probability: 0%
Published 2026-06-17T18:18:06.307 · Last modified 2026-06-25T17:43:39.240

Summary

Impact: undici's cookie parser in parseSetCookie percent-decodes cookie values via qsUnescape, turning encoded sequences like %0D%0A, %00, %3B, and %3D into their literal byte equivalents. RFC 6265 §5.4 does not specify any decoding and browsers do not decode either. Applications that parse a Set-Cookie header and then forward the parsed value into a response header (proxies, middleware, SSR frameworks) become vulnerable to HTTP response header injection: an attacker-controlled upstream can inject arbitrary Set-Cookie, Location, or Cache-Control headers into the application's downstream response, enabling session fixation, open redirect, or cache poisoning. Affected applications are those that use undici's cookie parsing (parseSetCookie, parseCookie, getSetCookies) and forward the parsed

Affected products

nodejs — undici

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.