{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-27199","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-02-18T19:47:02.155Z","datePublished":"2026-02-21T05:15:53.335Z","dateUpdated":"2026-02-24T19:02:19.689Z"},"containers":{"cna":{"title":"Werkzeug safe_join() allows Windows special device names","problemTypes":[{"descriptions":[{"cweId":"CWE-67","lang":"en","description":"CWE-67: Improper Handling of Windows Device Names","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","version":"4.0"}}],"references":[{"name":"https://github.com/pallets/werkzeug/security/advisories/GHSA-29vq-49wr-vm6x","tags":["x_refsource_CONFIRM"],"url":"https://github.com/pallets/werkzeug/security/advisories/GHSA-29vq-49wr-vm6x"},{"name":"https://github.com/pallets/werkzeug/commit/f407712fdc60a09c2b3f4fe7db557703e5d9338d","tags":["x_refsource_MISC"],"url":"https://github.com/pallets/werkzeug/commit/f407712fdc60a09c2b3f4fe7db557703e5d9338d"},{"name":"https://github.com/pallets/werkzeug/releases/tag/3.1.6","tags":["x_refsource_MISC"],"url":"https://github.com/pallets/werkzeug/releases/tag/3.1.6"}],"affected":[{"vendor":"pallets","product":"werkzeug","versions":[{"version":"< 3.1.6","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-02-21T05:15:53.335Z"},"descriptions":[{"lang":"en","value":"Werkzeug is a comprehensive WSGI web application library. Versions 3.1.5 and below, the safe_join function allows Windows device names as filenames if preceded by other path segments. This was previously reported as GHSA-hgf8-39gv-g3f2, but the added filtering failed to account for the fact that safe_join accepts paths with multiple segments, such as example/NUL. The function send_from_directory uses safe_join to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely. This issue has been fixed in version 3.1.6."}],"source":{"advisory":"GHSA-29vq-49wr-vm6x","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-02-24T19:02:05.165135Z","id":"CVE-2026-27199","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-02-24T19:02:19.689Z"}}]}}