{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-86099","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","state":"PUBLISHED","assignerShortName":"VulnCheck","dateReserved":"2026-09-04T22:51:17.817Z","datePublished":"2026-09-09T13:31:59.696Z","dateUpdated":"2026-09-09T14:49:36.459Z"},"containers":{"cna":{"providerMetadata":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-09-09T13:31:59.696Z"},"datePublic":"2026-09-03T00:00:00.000Z","title":"Chainlit through 2.12.0 Path Traversal via socket.io sessionId","descriptions":[{"lang":"en","value":"Chainlit through 2.12.0 fails to validate the client-supplied socket.io sessionId parameter, allowing unauthenticated attackers to traverse filesystem paths by injecting absolute or relative path sequences. Attackers can craft malicious sessionId values that escape the upload directory and recursively delete arbitrary directories accessible to the service process."}],"problemTypes":[{"descriptions":[{"lang":"en","description":"CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')","cweId":"CWE-22","type":"CWE"}]}],"affected":[{"defaultStatus":"unaffected","packageURL":"pkg:pypi/chainlit","vendor":"Chainlit","product":"chainlit","repo":"https://github.com/Chainlit/chainlit","collectionURL":"https://pypi.org/project/chainlit/","packageName":"chainlit","versions":[{"status":"affected","version":"0","versionType":"semver","lessThanOrEqual":"2.12.0"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:chainlit:chainlit:*:*:*:*:*:*:*:*","versionEndIncluding":"2.12.0"}]}]}],"metrics":[{"cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.8,"baseSeverity":"HIGH"}},{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"HIGH","baseScore":8.2,"baseSeverity":"HIGH"}}],"references":[{"url":"https://github.com/Chainlit/chainlit","name":"Product Repository","tags":["product"]},{"url":"https://github.com/Chainlit/chainlit/blob/2.12.0/backend/chainlit/session.py","name":"Vulnerable files_dir property and rmtree sink","tags":["technical-description"]},{"url":"https://github.com/Chainlit/chainlit/blob/2.12.0/backend/chainlit/socket.py","name":"Client-supplied sessionId assignment","tags":["technical-description"]},{"url":"https://pypi.org/project/chainlit/","name":"PyPI Package","tags":["product"]},{"name":"VulnCheck Advisory: Chainlit through 2.12.0 Path Traversal via socket.io sessionId","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/chainlit-through-2.12.0-path-traversal-via-socket-io-sessionid"}],"credits":[{"lang":"en","value":"mil4n","type":"finder"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-09T14:47:26.479403Z","id":"CVE-2026-86099","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"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":"2026-09-09T14:49:36.459Z"}}]}}