Vulnerability in Pydantic Pydantic-Ai
CVE-2026-107286
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Pydantic Pydantic-Ai — versions >= 2.10.0, < 2.53.0
- Pydantic Pydantic-Ai-Slim — versions >= 2.10.0, < 2.53.0
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-107286?
- CVE-2026-107286 is a high-severity vulnerability in Pydantic Pydantic-Ai, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 7.5/10. Published 2026-10-08.
- How severe is CVE-2026-107286?
- High severity. CVSS v3 base score is 7.5 out of 10.