{"id":"CVE-2026-106491","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-106491","generatedAt":"2026-10-28T02:20:53.248Z","title":"Prior to 0.6.17, the @backstage/plugin-proxy-backend package is affected by improper input validation in proxy-backend.","description":"Backstage is an open framework for building developer portals. Prior to 0.6.17, the @backstage/plugin-proxy-backend package is affected by improper input validation in proxy-backend. An authenticated Backstage user could craft a request URL that causes the proxy-backend to forward the request to a path outside the configured base path on the target server. This is limited to target servers already configured as proxy endpoints and requires Backstage authentication by default. This issue is fixed in version 0.6.17.","published":"2026-10-06T21:17:18.000Z","lastModified":"2026-10-22T14:10:06.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":6.4,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N"},"cwe":["CWE-20","CWE-22"],"affected":["linuxfoundation/backstage\\/plugin-proxy-backend","linuxfoundation/backstage"],"epss":{"score":0.00275,"percentile":0.1968,"date":"2026-10-26","history":[{"date":"2026-10-07","score":0.00268,"percentile":0.17393}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.27%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-06T21:17:18.000Z","detail":{"score":"6.4","severity":"MEDIUM","publishedAt":"2026-10-06T21:17:18.073Z"},"summary":"New CVE, medium severity (CVSS 6.4)."}],"references":[{"url":"https://github.com/backstage/backstage/commit/233287d0ce3133e41549bf92a7470c940a41753c","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/backstage/backstage/releases/tag/v1.54.6","tags":["Patch","Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/backstage/backstage/security/advisories/GHSA-9ghw-48h5-v2w5","tags":["Mitigation","Vendor Advisory"],"source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-106491","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}