EUVD-2026-95039
GHSA-6fqq-452j-qhrp
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AC:H because exploitation depends on a non-default shared long-lived limiter plus streaming configuration outside attacker control; PR:N/UI:N as triggering needs no auth; impact is availability-only (A:H).
Primary rating from Vendor (github).
CVSS VectorVendor: github
Lifecycle Timeline
4Blast Radius
ecosystem impact- 1 pypi packages depend on pydantic-ai (1 direct, 0 indirect)
- 5 pypi packages depend on pydantic-ai-slim (4 direct, 1 indirect)
Ecosystem-wide dependent count for version 2.10.0 and other introduced versions.
DescriptionCVE.org
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.
Articles & Coverage 1
AnalysisAI
Concurrency slot exhaustion in Pydantic AI 2.10.0 through 2.52.x lets streamed model requests permanently occupy slots in a shared ConcurrencyLimiter, progressively starving later requests until a service that reuses one long-lived limiter can no longer make model calls - an availability-only denial of service (C:N/I:N/A:H) with no confidentiality or integrity impact. The issue is remotely reachable and unauthenticated (PR:N), but our independent assessment rates it AC:H rather than GitHub's AC:L because exploitation requires a specific deployment pattern: model requests wrapped in ConcurrencyLimitedModel (or covered by limit_model_concurrency) that share a single long-lived limiter across streamed responses; agent-level max_concurrency and all non-streaming model requests are explicitly unaffected, and a short-lived or per-request limiter never accumulates enough leaked slots to deadlock. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
No credit card · 7-day full trial
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Requires the target application to wrap its model with ConcurrencyLimitedModel (or use limit_model_concurrency) and share a single long-lived ConcurrencyLimiter/anyio.CapacityLimiter instance across multiple requests, AND to use streaming model responses. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The GitHub-assigned CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, 7.5 HIGH) scores this as a remotely triggerable, unauthenticated availability-only issue (C:N/I:N), which aligns with CWE-772 (missing release of a resource - here, anyio.CapacityLimiter concurrency slots). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Vendor-released patch: upgrade to Pydantic AI 2.53.0 or later (`pip install --upgrade "pydantic-ai>=2.53.0"`, or the equivalent for pydantic-ai-slim), which is the version that resolves this advisory; see https://github.com/pydantic/pydantic-ai/releases/tag/v2.53.0 and GHSA-6fqq-452j-qhrp. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all applications using Pydantic AI versions 2.10.0 through 2.52.x and determine whether they use ConcurrencyLimitedModel or limit_model_concurrency with a shared long-lived limiter for streamed model requests; if so, temporarily disable streaming or switch to per-request or short-lived limiters. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
Wazuh SIEM platform versions 4.4.0 through 4.9.0 contain an unsafe deserialization vulnerability in the DistributedAPI t
BentoML version 1.4.2 and earlier contains an unauthenticated remote code execution vulnerability through insecure deser
pgAdmin 4 contains critical remote code execution vulnerabilities in the Query Tool download and Cloud Deployment endpoi
The renderLocalView function in render/views.py in graphite-web in Graphite 0.9.5 through 0.9.10 uses the pickle Python
BentoML is a Python library for building online serving systems optimized for AI apps and model inference. Rated critica
OpenSSL before 0.9.8za, 1.0.0 before 1.0.0m, and 1.0.1 before 1.0.1h does not properly restrict processing of ChangeCiph
pyLoad download manager version prior to 0.5.0b3.dev77 exposes the Flask SECRET_KEY through an unauthenticated endpoint.
Langflow (a visual LLM pipeline builder) contains a critical unauthenticated code execution vulnerability (CVE-2026-3301
In Mercurial before 4.1.3, "hg serve --stdio" allows remote authenticated users to launch the Python debugger, and conse
Unauthenticated remote code execution affects Kestra OSS (the open-source event-driven orchestration platform) prior to
Unauthenticated remote code execution in Marimo ≤0.20.4 allows attackers to execute arbitrary system commands via the `/
pyLoad is the free and open-source Download Manager written in pure Python. Rated medium severity (CVSS 5.3), this vulne
Same technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today