CVE-2026-42261

7.1 HIGH
Published: May 08, 2026 Modified: May 12, 2026
View on NVD

Description

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.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

Login to generate AI explanation

CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/legeling/PromptHub/releases/tag/v0.5.4
Source: security-advisories@github.com
Patch Product
https://github.com/legeling/PromptHub/security/advisories/GHSA-9fhh-fjfg-5mr6
Source: security-advisories@github.com
Exploit Mitigation Vendor Advisory
https://github.com/legeling/PromptHub/security/advisories/GHSA-9fhh-fjfg-5mr6
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Mitigation Vendor Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.1 / 10.0
EPSS (Exploit Probability)
0.2%
14th percentile
Exploitation Status
Not in CISA KEV

Affected Vendors

legeling