Is CVE-2026-115779 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-115779 being exploited in the wild.

How severe is CVE-2026-115779?

Medium severity, with a CVSS score of 4, published 3 November 2026.

Which products and versions are affected?

Effect-TS @Effect/Platform 0.1.0 through 0.97.0; Effect-TS Effect 4.0.0-beta.0 through 4.0.0-beta.102; @effect/platform (npm) >= 0.1.0, = 4.0.0-beta.0, < 4.0.0-beta.103, SEMVER:introduced=4.0.0-beta.0,fixed=4.0.0-beta.103.

Is there a fix for CVE-2026-115779?

Yes. @effect/platform (npm): upgrade to 0.97.1 or later; effect (npm): upgrade to 4.0.0-beta.103 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-115779 attacked?

It is attacked over the network.

Am I affected by CVE-2026-115779?

Check whether you run Effect-TS @Effect/Platform, Effect-TS Effect, @effect/platform (npm) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-115779: Effect TypeScript framework cookie injection in makeCookie()

Q: Is there a fix for CVE-2026-115779?

Yes. @effect/platform (npm): upgrade to 0.97.1 or later; effect (npm): upgrade to 4.0.0-beta.103 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-115779 attacked?

It is attacked over the network.

Q: Am I affected by CVE-2026-115779?

Check whether you run Effect-TS @Effect/Platform, Effect-TS Effect, @effect/platform (npm) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-115779 · Severity: medium · CVSS 4 · Published 2026-11-03

Effect is a TypeScript framework used to build web applications. The cookie-handling functions in the platform and core libraries allow attackers to inject unvalidated semicolons into cookie attributes, potentially expanding a cookie's scope across additional domains or adding attributes like SameSite=None that weaken security. An attacker who controls cookie input parameters can manipulate Set-Cookie headers to bypass intended security restrictions.

Technologies: effect (npm). Vendors: npm.

Quick answers

Is CVE-2026-115779 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-115779 being exploited in the wild.
How severe is CVE-2026-115779?: Medium severity, with a CVSS score of 4, published 3 November 2026.
Which products and versions are affected?: Effect-TS @Effect/Platform 0.1.0 through 0.97.0; Effect-TS Effect 4.0.0-beta.0 through 4.0.0-beta.102; @effect/platform (npm) >= 0.1.0, < 0.97.1, SEMVER:introduced=0.1.0,fixed=0.97.1; effect (npm) >= 4.0.0-beta.0, < 4.0.0-beta.103, SEMVER:introduced=4.0.0-beta.0,fixed=4.0.0-beta.103.
Is there a fix for CVE-2026-115779?: Yes. @effect/platform (npm): upgrade to 0.97.1 or later; effect (npm): upgrade to 4.0.0-beta.103 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-115779 attacked?: It is attacked over the network.
Am I affected by CVE-2026-115779?: Check whether you run Effect-TS @Effect/Platform, Effect-TS Effect, @effect/platform (npm) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

@effect/platform (npm): upgrade to 0.97.1 or later
```
npm install @effect/platform@0.97.1
```
effect (npm): upgrade to 4.0.0-beta.103 or later
```
npm install effect@4.0.0-beta.103
```

Technical details

The makeCookie() function in @effect/platform and effect framework versions prior to their fixes fail to validate semicolon characters in the name, domain, and path fields, allowing HTTP response splitting via Set-Cookie headers. An attacker supplying malicious input to these fields can inject additional cookie attributes or alter the Domain and SameSite constraints. The vulnerability affects @effect/platform 0.1.0–0.97.0 and effect 4.0.0-beta.0–4.0.0-beta.102; encoded values and CRLF characters are properly sanitized, limiting the attack surface.

Affected products

Effect-TS @effect/platform 0.1.0 through 0.97.0
Effect-TS effect 4.0.0-beta.0 through 4.0.0-beta.102

Identifiers

CVE-2026-115779
GHSA-chp3-j5qr-2vfr

Timeline

2026-11-03: disclosed: CVE published
2026-11-03: patched: Fixes available in @effect/platform 0.97.1 and effect 4.0.0-beta.103

References

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