Effect is a TypeScript framework that consists of several packages that work together to help build TypeScript applications. From @effect/platform 0.1.0 until 0.97.1 and effect 4.0.0-beta.0 until 4.0.0-beta.103, the name, domain, and path fields passed to makeCookie() allow semicolon delimiters that serializeCookie() writes verbatim into Set-Cookie headers. A caller that supplies attacker-controlled values can append cookie attributes, including a broader Domain or, when the caller has not set those options itself, SameSite=None or Max-Age. Encoded cookie values and CR or LF characters remain unaffected. This can widen a cookie's scope or add otherwise-unset cookie attributes. This issue is fixed in @effect/platform 0.97.1 and effect 4.0.0-beta.103.
https://github.com/Effect-TS/effect/security/advisories/GHSA-chp3-j5qr-2vfr
https://github.com/Effect-TS/effect/releases/tag/[email protected]
https://github.com/Effect-TS/effect/releases/tag/@effect/[email protected]
https://github.com/Effect-TS/effect/pull/6765
https://github.com/Effect-TS/effect/pull/6763
https://github.com/Effect-TS/effect/commit/5859b373b9be04d5037a594196b4743ad80379bd
https://github.com/Effect-TS/effect/commit/4a57af24011db1d66e947289d2f7ffc2074696d2
Published: 2026-11-03
Updated: 2026-11-03
Base Score: 6.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Severity: High
Base Score: 6.3
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Severity: Medium
EPSS: 0.00627