CVE-2026-107286
highPydantic AI is a Python agent framework for building applications and workflows with Generative AI.
Vendor / product: Pydantic — pydantic ai
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Affected products
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
References
- https://github.com/pydantic/pydantic-ai/commit/453f19feeb7ab1d789f9393b1723c6a73b3d77b2 security-advisories@github.com
- https://github.com/pydantic/pydantic-ai/pull/9478 security-advisories@github.com
- https://github.com/pydantic/pydantic-ai/releases/tag/v2.53.0 security-advisories@github.com
- https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-6fqq-452j-qhrp security-advisories@github.com