CVE-2026-42261 (GCVE-0-2026-42261)

Vulnerability from cvelistv5 – Published: 2026-05-08 03:11 – Updated: 2026-05-11 18:11
VLAI
Title
PromptHub: Authenticated SSRF via IPv6 filter bypass in `POST /api/skills/fetch-remote`
Summary
PromptHub is an all-in-one AI toolbox for prompt, skill, and agent management. From version 0.4.9 to before version 0.5.4, apps/web/src/routes/skills.ts exposes an authenticated endpoint POST /api/skills/fetch-remote that fetches a user-supplied URL server-side and reflects the response body (up to 5 MB) back to the caller. The SSRF protection in apps/web/src/utils/remote-http.ts (isPrivateIPv6) attempts to block private/loopback destinations, but multiple alternate-but-valid IPv6 representations bypass the check. The bypasses reach any IPv4 address (loopback, RFC1918, link-local) via IPv4-mapped IPv6 in hex form, and the canonical ::1 via any representation that isn't the literal string "::1". Any authenticated user (role: user or admin) can trigger the SSRF. On deployments configured with ALLOW_REGISTRATION=true — a supported and documented configuration — this means any internet user who can register. This issue has been patched in version 0.5.4.
Severity
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-11 18:10 UTC
CWE
  • CWE-20 - Improper Input Validation
  • CWE-693 - Protection Mechanism Failure
  • CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7895 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
legeling PromptHub Affected: >= 0.4.9, < 0.5.4
guessed Create a notification for this product.
Show details on NVD website
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