{"api_version":"1","generated_at":"2026-10-08T19:29:48+00:00","cve":"CVE-2026-107286","urls":{"html":"https://cve.report/CVE-2026-107286","api":"https://cve.report/api/cve/CVE-2026-107286.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-107286","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-107286"},"summary":{"title":"Pydantic AI: Concurrency-limited models can keep their slot when a streamed request ends early","description":"Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 2.10.0 until 2.53.0, streamed requests made through ConcurrencyLimitedModel or limit_model_concurrency can retain shared concurrency slots because anyio.CapacityLimiter associates an acquired slot with the borrowing task while streaming cleanup can run in a different task. Early stream termination, cancellation, consumer exceptions, or complete stream_text() consumption with debounce_by=0.1 can therefore leave capacity occupied, eventually preventing later requests that share the long-lived limiter from proceeding and causing a denial of service. Agent-level max_concurrency and non-streaming model requests are not affected. This issue is fixed in version 2.53.0.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-10-08 15:17:40","updated_at":"2026-10-08 18:17:16"},"problem_types":["CWE-772","CWE-772 CWE-772: Missing Release of Resource after Effective Lifetime"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-6fqq-452j-qhrp","name":"https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-6fqq-452j-qhrp","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/pydantic/pydantic-ai/releases/tag/v2.53.0","name":"https://github.com/pydantic/pydantic-ai/releases/tag/v2.53.0","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/pydantic/pydantic-ai/commit/453f19feeb7ab1d789f9393b1723c6a73b3d77b2","name":"https://github.com/pydantic/pydantic-ai/commit/453f19feeb7ab1d789f9393b1723c6a73b3d77b2","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/pydantic/pydantic-ai/pull/9478","name":"https://github.com/pydantic/pydantic-ai/pull/9478","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-107286","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107286","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"pydantic","product":"pydantic-ai","version":"affected >= 2.10.0, < 2.53.0","platforms":[]},{"source":"CNA","vendor":"pydantic","product":"pydantic-ai-slim","version":"affected >= 2.10.0, < 2.53.0","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-107286","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-10-08T17:26:50.651820Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-10-08T17:27:24.185Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"product":"pydantic-ai","vendor":"pydantic","versions":[{"status":"affected","version":">= 2.10.0, < 2.53.0"}]},{"product":"pydantic-ai-slim","vendor":"pydantic","versions":[{"status":"affected","version":">= 2.10.0, < 2.53.0"}]}],"descriptions":[{"lang":"en","value":"Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 2.10.0 until 2.53.0, streamed requests made through ConcurrencyLimitedModel or limit_model_concurrency can retain shared concurrency slots because anyio.CapacityLimiter associates an acquired slot with the borrowing task while streaming cleanup can run in a different task. Early stream termination, cancellation, consumer exceptions, or complete stream_text() consumption with debounce_by=0.1 can therefore leave capacity occupied, eventually preventing later requests that share the long-lived limiter from proceeding and causing a denial of service. Agent-level max_concurrency and non-streaming model requests are not affected. This issue is fixed in version 2.53.0."}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-772","description":"CWE-772: Missing Release of Resource after Effective Lifetime","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-08T15:12:26.597Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-6fqq-452j-qhrp","tags":["x_refsource_CONFIRM"],"url":"https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-6fqq-452j-qhrp"},{"name":"https://github.com/pydantic/pydantic-ai/pull/9478","tags":["x_refsource_MISC"],"url":"https://github.com/pydantic/pydantic-ai/pull/9478"},{"name":"https://github.com/pydantic/pydantic-ai/commit/453f19feeb7ab1d789f9393b1723c6a73b3d77b2","tags":["x_refsource_MISC"],"url":"https://github.com/pydantic/pydantic-ai/commit/453f19feeb7ab1d789f9393b1723c6a73b3d77b2"},{"name":"https://github.com/pydantic/pydantic-ai/releases/tag/v2.53.0","tags":["x_refsource_MISC"],"url":"https://github.com/pydantic/pydantic-ai/releases/tag/v2.53.0"}],"source":{"advisory":"GHSA-6fqq-452j-qhrp","discovery":"UNKNOWN"},"title":"Pydantic AI: Concurrency-limited models can keep their slot when a streamed request ends early"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-107286","datePublished":"2026-10-08T15:12:26.597Z","dateReserved":"2026-10-07T15:53:23.586Z","dateUpdated":"2026-10-08T17:27:24.185Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-08 15:17:40","lastModifiedDate":"2026-10-08 18:17:16","problem_types":["CWE-772","CWE-772 CWE-772: Missing Release of Resource after Effective Lifetime"],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-08T17:26:50.651820Z","id":"CVE-2026-107286","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"107286","Ordinal":"1","Title":"Pydantic AI: Concurrency-limited models can keep their slot when","CVE":"CVE-2026-107286","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"107286","Ordinal":"1","NoteData":"Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 2.10.0 until 2.53.0, streamed requests made through ConcurrencyLimitedModel or limit_model_concurrency can retain shared concurrency slots because anyio.CapacityLimiter associates an acquired slot with the borrowing task while streaming cleanup can run in a different task. Early stream termination, cancellation, consumer exceptions, or complete stream_text() consumption with debounce_by=0.1 can therefore leave capacity occupied, eventually preventing later requests that share the long-lived limiter from proceeding and causing a denial of service. Agent-level max_concurrency and non-streaming model requests are not affected. This issue is fixed in version 2.53.0.","Type":"Description","Title":"Pydantic AI: Concurrency-limited models can keep their slot when"}]}}}