Effect: Cookie attribute injection via domain, path, and name fields in @effect/platform makeCookie()
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 4.0.0-beta.103, 0.97.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 4.0.0-beta.103, 0.97.1.
- Exploitation0/40No signal
- Exposure17/25No login or user action needed per the CVSS vector, reachable over the network without a login · Data gap: No advisory context yet
- Reach?/20Reach: unknown (data gap). No tracked technology or package matched
- Severity6.3/10CVSS 6.3
- No patch0/5No signal
What would change the score
- Would score about 68 if added to CISA KEV
- Would score about 63 if CISA's SSVC rates exploitation active
- Would score about 28 if advisories confirm default setups are exposed
CVE-2026-115779 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.3 (medium) and affects effect and platform; fixed in 4.0.0-beta.103 and 0.97.1.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 23/100 · provisional
- Fix
- Fixed in 4.0.0-beta.103, 0.97.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
The Effect TypeScript framework's @effect/platform package and the effect 4.0 beta packages are affected when the cookie name, domain, or path passed to makeCookie() comes from untrusted input. An attacker can inject extra cookie attributes, such as a broader Domain, SameSite=None, or Max-Age, which can widen a cookie's scope or change its behavior.
Read the original 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.
What to do
Upgrade to a fixed version: 4.0.0-beta.103, 0.97.1.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Effect-TS effect
From 4.0.0-beta.0 · fixed in 4.0.0-beta.103
- @effect platform
From 0.1.0 · fixed in 0.97.1
Evidence 7
- Advisory
- Repository
- Repository
- Repository
- Repository
Show all 7 sourcesShow fewer sources
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-115779
Is CVE-2026-115779 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-115779?
effect: from 4.0.0-beta.0 before 4.0.0-beta.103. platform: from 0.1.0 before 0.97.1.Source: cve.now feed data
How do I fix CVE-2026-115779?
Upgrade to a fixed version: 4.0.0-beta.103, 0.97.1.Source: cve.now feed data