Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:NSummary
CVE-2026-32255 is a high-severity SSRF (CWE-918) vulnerability in Kan Kan. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-32255 is a server-side request forgery (SSRF) vulnerability, classified under CWE-918, affecting Kan, an open-source project management tool, in versions 0.5.4 and below. The issue lies in the /api/download/attatchment endpoint, which performs no authentication checks and lacks URL validation. This endpoint accepts a user-supplied URL via a query parameter, passes it directly to the server's fetch() function, and returns the full response body to the caller.
Unauthenticated remote attackers can exploit this vulnerability over the network with low complexity and no user interaction required. By crafting requests to the endpoint, attackers can force the Kan server to issue HTTP requests to arbitrary destinations, such as internal services, cloud metadata endpoints (e.g., on AWS, Azure, or GCP), or other private network resources. The CVSS v3.1 base score of 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N) underscores the high confidentiality impact achievable in a cross-scope attack scenario.
The vulnerability has been fixed in Kan version 0.5.5. As a workaround prior to upgrading, block or restrict access to the /api/download/attatchment endpoint at the reverse proxy level using tools like nginx or Cloudflare. Additional details are available in the GitHub security advisory (GHSA-qrx8-9hc6-jvqg), the patching commit (53397d8e81dc1494d94132848c1f0416f1152bd7), and the v0.5.5 release notes.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-12997
Vulnerability Data
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…
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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.).
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.3.6V1.5.3V5.3.2V10.4.7
Mitigating Controls (NIST 800-53 r5) AI
Information flow enforcement can restrict which destinations the server is allowed to contact on behalf of users.
Input validation directly stops untrusted URLs from being accepted and fetched without destination checks.
Boundary protection limits the network reach of server-initiated requests even if SSRF occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure development practices directly include input validation and destination allow-listing that prevent SSRF.
Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.
Vulnerability identification processes can discover and record SSRF flaws in web applications.
Network segmentation and egress controls can limit the damage from successful SSRF requests.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.