katalyst-koi: Session cookies can be replayed after user logout

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.0020, the 9th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the GitHub Advisory Database, published 7 May 2026. New records show when each source confirmed them.

Sources

• GitHub Advisory Database: GHSA-4cx3-3c38-j9vv
• OSV: GHSA-4cx3-3c38-j9vv
• github.com/katalyst/koi/security/advisories/GHSA-4cx3-3c38-j9vv
• nvd.nist.gov/vuln/detail/CVE-2026-44511
• github.com/katalyst/koi
• github.com/rubysec/ruby-advisory-db/blob/master/gems/katalyst-koi/CVE-2026-44511.yml
• guides.rubyonrails.org/v5.2.0/security.html#replay-attacks-for-cookiestore-sessions

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.