Vulnerability · Published Mar 18, 2026 · Assigned by GitHub_M

CVE-2026-32255Kan is Vulnerable to Unauthenticated SSRF via Attachment Download Endpoint

High 8.6

In plain English

A high-severity server-side request forgery in kan from kanbn. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 26.9% (higher than 98% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei, public proof-of-concept code.

Severity (CVSS 3.1)8.6High

Exploit odds (30 days)26.9%top 2.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack tooling2Nuclei, Public PoC

Official description

Kan is an open-source project management tool. In versions 0.5.4 and below, the /api/download/attatchment endpoint has no authentication and no URL validation. The Attachment Download endpoint accepts a user-supplied URL query parameter and passes it directly to fetch() server-side, and returns the full response body. An unauthenticated attacker can use this to make HTTP requests from the server to internal services, cloud metadata endpoints, or private network resources. This issue has been fixed in version 0.5.5. To workaround this issue, block or restrict access to /api/download/attatchment at the reverse proxy level (nginx, Cloudflare, etc.).

Affected products (as reported)

Vendor	Product	Versions
kanbn	kan	< 0.5.5

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

References

https://github.com/kanbn/kan/security/advisories/GHSA-qrx8-9hc6-jvqg x_refsource_CONFIRM
https://github.com/kanbn/kan/commit/53397d8e81dc1494d94132848c1f0416f1152bd7 x_refsource_MISC
https://github.com/kanbn/kan/releases/tag/v0.5.5 x_refsource_MISC