{"identifier":"CVE-2026-42261","cve":{"id":"CVE-2026-42261","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.","published":"2026-05-08T04:16:20.107000+00:00","modified":"2026-10-26T20:10:00.160000+00:00","status":"Analyzed","score":7.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","cvss_version":"3.1","affected":[{"criteria":"cpe:2.3:a:legeling:prompthub:*:*:*:*:-:*:*:*","versionStartIncluding":"0.4.9","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"0.5.4"}],"weaknesses":["CWE-20","CWE-693","CWE-918"],"references":[{"url":"https://github.com/legeling/PromptHub/releases/tag/v0.5.4","source":"security-advisories@github.com","tags":["Patch","Product"]},{"url":"https://github.com/legeling/PromptHub/security/advisories/GHSA-9fhh-fjfg-5mr6","source":"security-advisories@github.com","tags":["Exploit","Mitigation","Vendor Advisory"]},{"url":"https://github.com/legeling/PromptHub/security/advisories/GHSA-9fhh-fjfg-5mr6","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","tags":["Exploit","Mitigation","Vendor Advisory"]}],"kev":null,"kev_checked":true,"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","baseScore":7.1,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":2.8,"impactScore":4.2}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-05-11T18:10:25.854871Z","id":"CVE-2026-42261","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:legeling:prompthub:*:*:*:*:-:*:*:*","versionStartIncluding":"0.4.9","versionEndExcluding":"0.5.4","matchCriteriaId":"70AA7323-FB30-4401-9F87-B09372E70663"}]}]}],"source":"nvd","retrieved_at":"2026-10-28T10:20:09.019211+00:00","exploited":false,"kev_stale":false,"products":["legeling / prompthub"],"priority":{"label":"Assess exposure and vendor guidance","reasons":["No higher-priority signal is available in the current stored evidence."]},"epss":{"probability":0.00237,"percentile":0.1471,"date":"2026-10-29","stale":false},"version_assessment":null},"news":[],"campaigns":[],"domains":[{"domain":"github.com","source_url":"https://github.com/legeling/PromptHub/releases/tag/v0.5.4","investigate_url":"https://investigate.aeglixmind.com/#github.com"}],"arsenal_url":"https://arsenal.aeglixmind.com/?cve=CVE-2026-42261","catalog_url":"https://cves.aeglixmind.com/cve/CVE-2026-42261","research_url":"https://investigate.aeglixmind.com/research/cve/CVE-2026-42261","coverage":{"news_candidates_checked":0,"campaign_candidates_checked":0,"bounded":false,"notice":"Exact CVE mentions in stored public excerpts and reviewed campaign content only. A mention is not proof of exploitation, attribution or tool suitability. Missing matches do not establish absence."}}