Vulnerability in kanbn kan

[ Description ]Official description

Kan 0.5.5 through 0.6.0 contains an unauthenticated server-side request forgery vulnerability in the /api/download/attatchment route due to an incomplete fix for CVE-2026-32255. When S3_ENDPOINT is unset, attackers can pass arbitrary url query parameters to fetch() to read internal services, localhost ports, and cloud instance metadata.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References

• github.com/kanbn/kan
• github.com/kanbn/kan/blob/v0.6.0/.env.example
• github.com/kanbn/kan/blob/v0.6.0/apps/web/src/pages/api/download/attatchment.ts
• github.com/kanbn/kan/commit/53397d8e81dc1494d94132848c1f0416f1152bd7
• github.com/kanbn/kan/pull/590
• github.com/kanbn/kan/security/advisories/GHSA-qrx8-9hc6-jvqg
• hackmd.io/@leediay/HyIxU63ofg
• www.vulncheck.com/advisories/kan-0.5.5-through-0.6.0-unauthenticated-ssrf-via-api-downl…