by Kastro
Paper/Archive/CVE-2026-110628

CVE-2026-110628

kanbn kan — Kan 0.5.5 through 0.6.0 Unauthenticated SSRF via /api/download/attatchment

EPSS 0.4%CVSS 9.2
critical.is priorityof 100
35
CVSS 9.2 (CNA)9.2 / 10 × 3027.6Not in CISA KEV+300.0EPSS percentile 36.7.367 × 207.3No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
kan0.5.5 – 0.6.0–CNA

Scores by source

VulnCheck (CNA)9.2CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
VulnCheck (CNA)8.6CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: partial

References

writeuphackmd.io/@leediay/HyIxU63ofgpatchgithub.com/kanbn/kan/pull/590writeupgithub.com/kanbn/kan/blob/v0.6.0/apps/web/src/pages/api/download/attatchment.ts#L21-L52writeupgithub.com/kanbn/kan/blob/v0.6.0/.env.example#L25-L27advisorygithub.com/kanbn/kan/security/advisories/GHSA-qrx8-9hc6-jvqgpatchgithub.com/kanbn/kan/commit/53397d8e81dc1494d94132848c1f0416f1152bd7refgithub.com/kanbn/kanwriteupvulncheck.com/advisories/kan-0.5.5-through-0.6.0-unauthenticated-ssrf-via-api-download-attatchment