Answer in brief
CVE-2026-107286 records a High severity (CVSS 7.5) vulnerability in Pydantic AI: Concurrency-limited models can keep their slot when a streamed request ends early. The current sources do not mark it as known exploited. The current feed maps pydantic/pydantic-ai (generic), pydantic/pydantic-ai-slim (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps pydantic/pydantic-ai (generic), pydantic/pydantic-ai-slim (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| pydantic/pydantic-aigeneric | >=2.10.0 <2.53.0 | 2.53.0 |
| pydantic/pydantic-ai-slimgeneric | >=2.10.0 <2.53.0 | 2.53.0 |
Published upstream
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 8, 2026
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.
Quoted source text, attributed separately from HOL analysis.