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

Source: https://junglewise.ai/threats/cve-2026-115779-effect-is-a-typescript-framework-that-consists-of-several  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-03. Updated: 2026-11-03  
License: CC BY 4.0 with a link back

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)](https://junglewise.ai/threats/technologies/effect). Vendors: [npm](https://junglewise.ai/threats/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

  ```sh
  npm install @effect/platform@0.97.1
  ```

- effect (npm): upgrade to 4.0.0-beta.103 or later

  ```sh
  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

- [https://github.com/Effect-TS/effect/commit/4a57af24011db1d66e947289d2f7ffc2074696d2](https://github.com/Effect-TS/effect/commit/4a57af24011db1d66e947289d2f7ffc2074696d2)
- [https://github.com/Effect-TS/effect/commit/5859b373b9be04d5037a594196b4743ad80379bd](https://github.com/Effect-TS/effect/commit/5859b373b9be04d5037a594196b4743ad80379bd)

## Related threats

- [Effect AsyncLocalStorage context contamination in concurrent RPC handlers](https://junglewise.ai/threats/cve-2026-32887-effect-ts-effect-asynclocalstorage-context-contamination-in)
- [effect OS command injection (withdrawn)](https://junglewise.ai/threats/cve-2020-7624-effect-os-command-injection-withdrawn)