{"id":"CVE-2026-75156","state":"PUBLISHED","title":"Apache Airflow FAB provider: FAB Azure AD OAuth: id_token issuer/audience not validated — cross-tenant authentication bypass","description":"Apache Airflow FAB provider versions 3.7.3 through 3.8.0 do not validate the issuer or audience of Azure AD `id_token`s during OAuth login. Deployments are affected only when the FAB auth manager is configured with Azure AD as an OAuth provider. Because the signing keys are fetched from Microsoft's **multi-tenant** JWKS endpoint, an `id_token` minted in *any* Azure tenant — including one the attacker creates — passes signature verification, and the username and role assignments are then read from that attacker-controlled token. Anyone able to register an Azure tenant can therefore authenticate to the Airflow UI with no prior access to the deployment.\n\nThe fix for **CVE-2026-59243** was incomplete, and this advisory closes the remaining gap: that fix made the provider verify the `id_token` signature, but did not add issuer or audience checks. Operators who already applied the CVE-2026-59243 fix are **still affected and must upgrade again** — 3.7.3 is the release that shipped that fix, so every version containing it falls inside this affected range. Upgrade to apache-airflow-providers-fab `3.8.1` or later.","publishedAt":"2026-09-08T16:47:48.290Z","updatedAt":"2026-09-16T14:57:01.780Z","severity":{"score":9.1,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","source":"CISA-ADP"},"assigner":"apache","products":["Apache Software Foundation Apache Airflow FAB provider"],"affected":[{"vendor":"Apache Software Foundation","product":"Apache Airflow FAB provider","packageName":"apache-airflow-providers-fab","packageURL":"pkg:pypi/apache-airflow-providers-fab","defaultStatus":"unaffected","versions":[{"version":"3.7.3","status":"affected","lessThan":"3.8.1","versionType":"semver"}],"collectionURL":"https://pypi.python.org"}],"references":["https://github.com/apache/airflow/pull/71735","https://lists.apache.org/thread/n3l6z4jfdxj4p0t8l7m6olkq6xsc6f76","https://www.cve.org/CVERecord?id=CVE-2026-59243"],"weaknesses":["CWE-346"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/75xxx/CVE-2026-75156.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-75156","state":"PUBLISHED","datePublished":"2026-09-08T16:47:48.290Z","dateUpdated":"2026-09-16T14:57:01.780Z","assignerShortName":"apache","assignerOrgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","dateReserved":"2026-08-17T18:58:02.812Z"},"containers":{"cna":{"title":"Apache Airflow FAB provider: FAB Azure AD OAuth: id_token issuer/audience not validated — cross-tenant authentication bypass","descriptions":[{"lang":"en","value":"Apache Airflow FAB provider versions 3.7.3 through 3.8.0 do not validate the issuer or audience of Azure AD `id_token`s during OAuth login. Deployments are affected only when the FAB auth manager is configured with Azure AD as an OAuth provider. Because the signing keys are fetched from Microsoft's **multi-tenant** JWKS endpoint, an `id_token` minted in *any* Azure tenant — including one the attacker creates — passes signature verification, and the username and role assignments are then read from that attacker-controlled token. Anyone able to register an Azure tenant can therefore authenticate to the Airflow UI with no prior access to the deployment.\n\nThe fix for **CVE-2026-59243** was incomplete, and this advisory closes the remaining gap: that fix made the provider verify the `id_token` signature, but did not add issuer or audience checks. Operators who already applied the CVE-2026-59243 fix are **still affected and must upgrade again** — 3.7.3 is the release that shipped that fix, so every version containing it falls inside this affected range. Upgrade to apache-airflow-providers-fab `3.8.1` or later."}],"affected":[{"vendor":"Apache Software Foundation","product":"Apache Airflow FAB provider","packageName":"apache-airflow-providers-fab","packageURL":"pkg:pypi/apache-airflow-providers-fab","defaultStatus":"unaffected","versions":[{"version":"3.7.3","status":"affected","lessThan":"3.8.1","versionType":"semver"}],"collectionURL":"https://pypi.python.org"}],"references":[{"url":"https://github.com/apache/airflow/pull/71735","tags":["patch"]},{"url":"https://lists.apache.org/thread/n3l6z4jfdxj4p0t8l7m6olkq6xsc6f76","tags":["vendor-advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-59243","tags":["related"]}],"metrics":[{"other":{"content":{"text":"moderate"},"type":"Textual description of severity"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-346","description":"CWE-346: Origin Validation Error","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"apache","orgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","dateUpdated":"2026-09-16T14:57:01.780Z"},"credits":[{"lang":"en","type":"finder","value":"Roberto Nunes"},{"lang":"en","type":"tool","value":"NEO AI Engineer (@neo-ai-engineer, ProjectDiscovery)"},{"lang":"en","type":"remediation developer","value":"Jarek Potiuk"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"airflow-s/generate_cve_json.py"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":9.1,"attackVector":"NETWORK","baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-09-08T18:59:35.794768Z","id":"CVE-2026-75156","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-08T19:00:04.858Z"}}]}}}