{"id":"CVE-2026-39977","state":"PUBLISHED","title":"flatpak-builder has a path traversal leading to arbitrary file read on host when installing licence files","description":"flatpak-builder is a tool to build flatpaks from source. From 1.4.5 to before 1.4.8, the license-files manifest key takes an array of paths to user defined licence files relative to the source directory of the module. The paths from that array are resolved using g_file_resolve_relative_path() and validated to stay inside the source directory using two checks - g_file_get_relative_path() which does not resolve symlinks and g_file_query_file_type() with G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS which only applies to the final path component. The copy operation runs on host. This can be exploited by using a crafted manifest and/or source to read arbitrary files from the host and capture them into the build output. This vulnerability is fixed in 1.4.8.","publishedAt":"2026-04-09T19:05:23.616Z","updatedAt":"2026-04-09T20:19:28.323Z","severity":{"score":7.1,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["flatpak flatpak-builder"],"affected":[{"vendor":"flatpak","product":"flatpak-builder","versions":[{"version":">= 1.4.5, < 1.4.8","status":"affected"}]}],"references":["https://github.com/flatpak/flatpak-builder/security/advisories/GHSA-6gm9-3g7m-3965"],"weaknesses":["CWE-22"],"ingestedAt":"2026-10-29T20:11:50.837Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/39xxx/CVE-2026-39977.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-39977","state":"PUBLISHED","datePublished":"2026-04-09T19:05:23.616Z","dateUpdated":"2026-04-09T20:19:28.323Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-08T00:01:47.628Z"},"containers":{"cna":{"title":"flatpak-builder has a path traversal leading to arbitrary file read on host when installing licence files","descriptions":[{"lang":"en","value":"flatpak-builder is a tool to build flatpaks from source. From 1.4.5 to before 1.4.8, the license-files manifest key takes an array of paths to user defined licence files relative to the source directory of the module. The paths from that array are resolved using g_file_resolve_relative_path() and validated to stay inside the source directory using two checks - g_file_get_relative_path() which does not resolve symlinks and g_file_query_file_type() with G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS which only applies to the final path component. The copy operation runs on host. This can be exploited by using a crafted manifest and/or source to read arbitrary files from the host and capture them into the build output. This vulnerability is fixed in 1.4.8."}],"affected":[{"vendor":"flatpak","product":"flatpak-builder","versions":[{"version":">= 1.4.5, < 1.4.8","status":"affected"}]}],"references":[{"url":"https://github.com/flatpak/flatpak-builder/security/advisories/GHSA-6gm9-3g7m-3965","name":"https://github.com/flatpak/flatpak-builder/security/advisories/GHSA-6gm9-3g7m-3965","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":7.1,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-22","lang":"en","description":"CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-09T19:05:23.616Z"},"source":{"advisory":"GHSA-6gm9-3g7m-3965","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-09T20:18:06.098366Z","id":"CVE-2026-39977","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-09T20:19:28.323Z"}}]}}}