{"cve":"CVE-2026-107290","nvd":{"published":"2026-10-08T17:17:14.413","modified":"2026-10-13T14:34:38.623","status":"Analyzed","description":"Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.77.0 until 1.107.6 and 2.44.0, the local web_fetch_tool and the WebFetch local fallback process server-controlled responses with quadratic title extraction, whitespace normalization, and ordered-list numbering. An attacker-controlled page of modest size can therefore block the event loop for an extended period, stalling other agent runs and requests, while unsupported codecs or excessive HTML or JSON nesting can abort an individual run. This issue is fixed in versions 1.107.6 and 2.44.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-1333"],"references":["https://github.com/pydantic/pydantic-ai/commit/2faa6181d8a17d83bc9516d035c5270db8730fa0","https://github.com/pydantic/pydantic-ai/commit/9cdc952e4c3319e85a3e04f2de49fbbb765bd38b","https://github.com/pydantic/pydantic-ai/commit/a93ea5226be1e93ae13131ae3f22287190411389","https://github.com/pydantic/pydantic-ai/commit/c3fd1cc1f15fdbf750d78e4e3ec1e8b4d6a3d920","https://github.com/pydantic/pydantic-ai/commit/fb92ccfc3ca2735dab877e2ed73856681bf72ad1"],"products":["pydantic:pydantic_ai"],"source":"nvd","synced_at":"2026-10-19T22:58:01.639778232+00:00"},"epss":{"cve":"CVE-2026-107290","score":0.00512,"percentile":0.43366,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-fpf4-vwcp-v4hp","url":"https://osv.dev/vulnerability/GHSA-fpf4-vwcp-v4hp","summary":"Pydantic AI: Event loop blocked by quadratic title extraction in `web_fetch`","modified":"2026-10-15T14:56:08.216259462Z","packages":[{"ecosystem":"PyPI","name":"pydantic-ai","purl":"pkg:pypi/pydantic-ai","ranges":[">=1.77.0 <1.107.6"],"fixed":["1.107.6"]},{"ecosystem":"PyPI","name":"pydantic-ai","purl":"pkg:pypi/pydantic-ai","ranges":[">=2.0.0b1 <2.44.0"],"fixed":["2.44.0"]},{"ecosystem":"PyPI","name":"pydantic-ai-slim","purl":"pkg:pypi/pydantic-ai-slim","ranges":[">=1.77.0 <1.107.6"],"fixed":["1.107.6"]},{"ecosystem":"PyPI","name":"pydantic-ai-slim","purl":"pkg:pypi/pydantic-ai-slim","ranges":[">=2.0.0b1 <2.44.0"],"fixed":["2.44.0"]}]},{"id":"PYSEC-2026-4277","url":"https://osv.dev/vulnerability/PYSEC-2026-4277","summary":"Pydantic AI: Event loop blocked by quadratic title extraction in `web_fetch`","modified":"2026-10-15T14:56:08.216259462Z","packages":[{"ecosystem":"PyPI","name":"pydantic-ai","purl":"pkg:pypi/pydantic-ai","ranges":[">=1.77.0 <1.107.6",">=2.0.0b1 <2.44.0"],"fixed":["1.107.6","2.44.0"]}]},{"id":"PYSEC-2026-4286","url":"https://osv.dev/vulnerability/PYSEC-2026-4286","summary":"Pydantic AI: Event loop blocked by quadratic title extraction in `web_fetch`","modified":"2026-10-15T14:56:08.216259462Z","packages":[{"ecosystem":"PyPI","name":"pydantic-ai-slim","purl":"pkg:pypi/pydantic-ai-slim","ranges":[">=1.77.0 <1.107.6",">=2.0.0b1 <2.44.0"],"fixed":["1.107.6","2.44.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}