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Vulnerability · Published Nov 3, 2026 · Assigned by GitHub_M

CVE-2026-115779Effect: Cookie attribute injection via domain, path, and name fields in @effect/platform makeCookie()

Medium 6.3

In plain English

A medium-severity injection in platform from @effect. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities).

Severity (CVSS 4.0)6.3Medium
Exploit odds (30 days)0.6%top 49.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
Effect-TS effect >= 4.0.0-beta.0, < 4.0.0-beta.103
@effect platform >= 0.1.0, < 0.97.1

Weakness: CWE-74 · 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

References