{"answers":{"affected":"2 open source packages ship an affected version, including @backstage/plugin-proxy-backend. It affects 2 products.","exploited":"There is no known exploitation of CVE-2026-106491 in the wild and no public exploit code.","fix":"Upgrade @backstage/plugin-proxy-backend to 0.6.17 or later.","what":"CVE-2026-106491 is a medium-severity path traversal vulnerability in Linuxfoundation Backstage, published on 6 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-106491 and fix it if it is affected.\n\nWhat it is: CVE-2026-106491 is a medium-severity path traversal vulnerability in Linuxfoundation Backstage, published on 6 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-106491 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- @backstage/plugin-proxy-backend (npm): affected all versions; fixed in 0.6.17\n- @backstage/plugin-proxy-backend (npm): affected all versions; fixed in 0.6.17\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-106491/ (Markdown: https://insights.sbomify.com/CVE-2026-106491/index.md)","id":"CVE-2026-106491","markdown":"https://insights.sbomify.com/CVE-2026-106491/index.md","name":"CVE-2026-106491","record":{"aliases":["GHSA-9ghw-48h5-v2w5"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["data_read","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Backstage developer portal","requires_auth":"low_privilege","summary":"Authenticated users can bypass proxy restrictions to access unauthorized paths on configured target servers in Backstage.","user_interaction":"not_required","vuln_class":"path_traversal"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"backstage","vendor":"linuxfoundation"},{"product":"backstage\\/plugin-proxy-backend","vendor":"linuxfoundation"}],"cvss":{"score":6.4,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-22","name":"Improper Limitation of a Pathname to a Restricted Directory"},{"id":"CWE-20","name":"Improper Input Validation"}],"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.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Backstage: Improper input validation in proxy-backend","id":"CVE-2026-106491","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":"linuxfoundation:backstage","products":["linuxfoundation:backstage"],"type":"path_traversal","year":"2026"},"n_packages":2,"n_references":3,"next":{"headline":"Backstage: Improper preservation of access restrictions during service credential delegation","id":"CVE-2026-106492"},"packages":[{"ecosystem":"npm","fixed":["0.6.17"],"introduced":["0"],"last_affected":[],"package":"@backstage/plugin-proxy-backend","purl":null,"source":"GHSA-9ghw-48h5-v2w5"},{"ecosystem":"npm","fixed":["0.6.17"],"introduced":["0"],"last_affected":[],"package":"@backstage/plugin-proxy-backend","purl":"pkg:npm/%40backstage/plugin-proxy-backend","source":"GHSA-9ghw-48h5-v2w5"}],"prev":{"headline":"Backstage: Improper input validation in TechDocs static content requests","id":"CVE-2026-106490"},"products":["backstage","plugin-proxy-backend"],"published":"2026-10-06","related":[{"cvss_score":9.6,"headline":"Backstage: Sensitive information exposure in Scaffolder","id":"CVE-2026-106501","kev_date_added":null,"published":"2026-10-06"},{"cvss_score":8.8,"headline":"Backstage: Improper validation of TechDocs MkDocs configuration","id":"CVE-2026-106558","kev_date_added":null,"published":"2026-10-07"},{"cvss_score":8.8,"headline":"Backstage: Improper input validation in TechDocs MkDocs configuration","id":"CVE-2026-88064","kev_date_added":null,"published":"2026-09-16"},{"cvss_score":8.5,"headline":"Backstage: Improper input validation in Sentry scaffolder actions","id":"CVE-2026-106459","kev_date_added":null,"published":"2026-10-06"},{"cvss_score":8.5,"headline":"Backstage: Improper filesystem validation in Bitbucket pull-request scaffolder actions","id":"CVE-2026-106486","kev_date_added":null,"published":"2026-10-06"},{"cvss_score":8.5,"headline":"Backstage: Improper task state validation in Scaffolder backend","id":"CVE-2026-106500","kev_date_added":null,"published":"2026-10-06"},{"cvss_score":8.5,"headline":"Path Traversal in @backstage/plugin-scaffolder-backend","id":"CVE-2021-43783","kev_date_added":null,"published":"2021-11-29"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-07","vendors":["@backstage","backstage"]},"summary":"Authenticated users can bypass proxy restrictions to access unauthorized paths on configured target servers in Backstage.","url":"https://insights.sbomify.com/CVE-2026-106491/"}