{"schemaVersion":3,"id":"CVE-2026-55255","aliases":["GHSA-qrpv-q767-xqq2","PYSEC-2026-221"],"status":"published","duplicateOf":null,"title":"Langflow Authorization Bypass Through User-Controlled Key Vulnerability","description":"Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.","dates":{"published":"2026-06-23T16:28:20.985Z","modified":"2026-10-07T18:13:46.054Z","reserved":null,"kevAdded":["2026-07-07T00:00:00.000Z"],"kevDue":["2026-07-10T00:00:00.000Z"]},"cvss":{"headline":{"score":8.4,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":8.4,"severity":"high","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Pypi","score":9.9,"severity":"critical","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L","exploitability":7.9,"impact":10,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":8.4,"severity":"high","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00887,"percentile":0.58833,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-21T00:00:00.000Z","baselineScore":0.00887},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00887,"percentile":0.58833}],"last30":[{"date":"2026-09-21T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00887,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00887,"percentile":0.58833}]},"kev":{"state":"listed","entries":[{"source":"cisa","sourceLabel":"CISA","dateAdded":"2026-07-07T00:00:00.000Z","dueDate":"2026-07-10T00:00:00.000Z","requiredAction":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","name":"Langflow Authorization Bypass Through User-Controlled Key Vulnerability","description":"Langflow contains an authorization bypass through user-controlled key vulnerability which allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request.","notes":[{"type":"url","href":"https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2","label":"github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2"},{"type":"text","value":"BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk"},{"type":"text","value":"Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk"},{"type":"url","href":"https://nvd.nist.gov/vuln/detail/CVE-2026-55255","label":"nvd.nist.gov/vuln/detail/CVE-2026-55255"}],"vendor":"Langflow","product":"Langflow","ransomware":false,"ransomwareUse":"Unknown","exploitationType":null}],"listedCount":1,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":true,"entry":{"source":"cisa","sourceLabel":"CISA","dateAdded":"2026-07-07T00:00:00.000Z","dueDate":"2026-07-10T00:00:00.000Z","requiredAction":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","name":"Langflow Authorization Bypass Through User-Controlled Key Vulnerability","description":"Langflow contains an authorization bypass through user-controlled key vulnerability which allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request.","notes":[{"type":"url","href":"https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2","label":"github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2"},{"type":"text","value":"BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk"},{"type":"text","value":"Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk"},{"type":"url","href":"https://nvd.nist.gov/vuln/detail/CVE-2026-55255","label":"nvd.nist.gov/vuln/detail/CVE-2026-55255"}],"vendor":"Langflow","product":"Langflow","ransomware":false,"ransomwareUse":"Unknown","exploitationType":null}},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[{"id":"GITHUB_LANGFLOW-AI_LANGFLOW","name":"Langflow","source":"github","url":"https://github.com/langflow-ai/langflow/issues/1973","maturity":"poc","reliabilityScore":0.3,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null}],"exploitCount":1,"weaknesses":[{"id":"CWE-639","name":"Authorization Bypass Through User-Controlled Key","description":"The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.","type":"weakness","status":"Incomplete","abstraction":"Base","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/639.html"}],"affected":[{"vendor":"langflow-ai","product":"langflow","name":"langflow","label":"langflow","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 1.9.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.9.1","eol":null,"hubHref":"/vendor/langflow-ai/langflow"},{"vendor":"langflow","product":"langflow","name":"Langflow","label":"langflow","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 1.9.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.9.1","eol":null,"hubHref":"/vendor/langflow/langflow"},{"vendor":"PyPI","product":"langflow","name":"langflow","label":"langflow","ecosystem":"PyPI","cpePart":null,"purl":"pkg:pypi/langflow","purlType":"pypi","versions":[{"text":"< 1.9.1","noFixRecorded":false,"fixedIn":null},{"text":"< 1.9.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.9.1 | < 1.9.2","eol":null,"hubHref":null}],"affectedCount":3,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2","label":"github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2","hostname":"github.com","tags":["X Refsource CONFIRM","WEB","EVIDENCE","Exploit","Mitigation","Vendor Advisory"]},{"url":"https://github.com/langflow-ai/langflow/pull/12832","label":"github.com/langflow-ai/langflow/pull/12832","hostname":"github.com","tags":["X Refsource MISC","WEB","FIX","Issue Tracking","Patch"]},{"url":"https://github.com/langflow-ai/langflow/commit/2c9f498d664a3c32698b57d7c5e752625291060e","label":"github.com/langflow-ai/langflow/commit/2c9f498d664a3c32698b57d7c5e752625291060e","hostname":"github.com","tags":["X Refsource MISC","WEB","Patch"]},{"url":"https://webflow.sysdig.com/blog/understanding-langflow-cve-2026-55255-and-why-higher-cvss-vulnerabilities-arent-always-the-most-exploited","label":"webflow.sysdig.com/blog/…","hostname":"webflow.sysdig.com","tags":["Third Party Advisory","WEB"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55255","label":"www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55255","hostname":"www.cisa.gov","tags":["Government Resource","WEB","US Government Resource"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55255","label":"nvd.nist.gov/vuln/detail/CVE-2026-55255","hostname":"nvd.nist.gov","tags":["Advisory"]},{"url":"https://github.com/langflow-ai/langflow","label":"github.com/langflow-ai/langflow","hostname":"github.com","tags":["PACKAGE"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/langflow/PYSEC-2026-221.yaml","label":"github.com/pypa/advisory-database/tree/main/vulns/langflow/PYSEC-2026-221.yaml","hostname":"github.com","tags":["WEB"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-06-23T16:28:20.985Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"kev-added","date":"2026-07-07T00:00:00.000Z","label":"Added to CISA KEV","detail":"Langflow Authorization Bypass Through User-Controlled Key Vulnerability","source":"cisa"},{"kind":"kev-due","date":"2026-07-10T00:00:00.000Z","label":"CISA remediation due","detail":"Apply mitigations per vendor instructions.","source":"cisa"},{"kind":"modified","date":"2026-10-07T18:13:46.054Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":85,"level":"critical","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T16:44:27.593Z","stale":false,"partial":false}}