CVE-2026-107286
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.45%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.45% probability · 39th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-772
- Affected
- pydantic/pydantic ai
- Source
- security-advisories@github.com
EPSS moved from 0.4% on 9 October 2026 to 0.4% on 26 October 2026.
References
- https://github.com/pydantic/pydantic-ai/commit/453f19feeb7ab1d789f9393b1723c6a73b3d77b2Patch
- https://github.com/pydantic/pydantic-ai/pull/9478Patch, Vendor Advisory
- https://github.com/pydantic/pydantic-ai/releases/tag/v2.53.0Patch, Release Notes, Vendor Advisory
- https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-6fqq-452j-qhrpMitigation, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.