All vulnerabilities
CVE-2026-107294GHSA-v2xh-2vp8-57h8PYSEC-2026-4280PYSEC-2026-4289

pydantic-ai: Pydantic AI: Unbounded memory use when downloading remote content via web_fetch or FileUrl

pydantic pydantic-aipipLibraries & packages
Open in ThreatlineRecord JSON
CVSS
6.5Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.44%Chance of exploitation activity in the next 30 days, higher than 36% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in1.107.2Also 2.24.0GitHub
Published8 Oct 2026Updated 15 Oct 2026CVE List

What fixes it

  • 1.107.2pydantic-ai, pipGitHub
  • 2.24.0pydantic-ai, pipGitHub
  • 1.107.2pydantic-ai-slim, pipGitHub
  • 2.24.0pydantic-ai-slim, pipGitHub
  • 1.107.2pydantic-ai, PyPIOSVpip install "pydantic-ai>=1.107.2"
  • 2.24.0pydantic-ai, PyPIOSVpip install "pydantic-ai>=2.24.0"
Show all 8 fixed versions
  • 1.107.2pydantic-ai-slim, PyPIOSVpip install "pydantic-ai-slim>=1.107.2"
  • 2.24.0pydantic-ai-slim, PyPIOSVpip install "pydantic-ai-slim>=2.24.0"

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

Summary

Several remote-content download paths in Pydantic AI buffered the entire HTTP response body into memory before enforcing any size limit. An application that exposes the local web-fetch tool (web_fetch_tool, or the WebFetch capability's local fallback) to untrusted prompts can be driven to fetch an attacker-chosen URL that streams a very large body, exhausting process memory and crashing the worker. The same unbounded buffering applied to FileUrl media downloads (ImageUrl, DocumentUrl, VideoUrl, AudioUrl).

This is an availability issue only. SSRF protections (scheme allowlist, private-IP and cloud-metadata blocking) are unaffected; there is no confidentiality or integrity impact.

Details

The download helpers read the full response body before applying content-size controls, so an existing text-length limit only truncated *after* the whole body was already in memory, and media downloads had no wire-level cap at all. A single large response could grow process memory without bound .

Who Is Affected

You are affected if your application registers the local web-fetch tool (or relies on the WebFetch capability's local fallback) and exposes the agent to untrusted prompts, or if it downloads large remote FileUrls influenced by untrusted input. Applications that only fetch developer-controlled URLs are not exposed to the model-chosen attack path.

Remediation

Upgrade to 2.24.0 or later (v2) or 1.107.2 or later (v1). Patched versions enforce a default 50 MiB cap on web-fetch and FileUrl downloads while streaming; pass None to the limit to restore the previous unbounded behavior.

Credits

Identified during internal review of media-download hardening.

Text from GitHub Advisory Database

Affected versions 156

  • pydantic-ai, pip>= 1.77.0, < 1.107.2GitHub
  • pydantic-ai, pip>= 2.0.0b1, <= 2.23.0GitHub
  • pydantic-ai-slim, pip>= 1.77.0, < 1.107.2GitHub
  • pydantic-ai-slim, pip>= 2.0.0b1, <= 2.23.0GitHub
  • pydantic-aiaffected: >= 1.77.0, < 1.107.2CVE List
  • pydantic-aiaffected: >= 2.0.0b1, < 2.24.0CVE List
  • pydantic-ai-slimaffected: >= 1.77.0, < 1.107.2CVE List
  • pydantic-ai-slimaffected: >= 2.0.0b1, < 2.24.0CVE List
  • pydantic-ai, PyPIfrom 1.77.0, fixed in 1.107.2OSV
  • pydantic-ai, PyPI1.100.0OSV
  • pydantic-ai, PyPI1.101.0OSV
  • pydantic-ai, PyPI1.102.0OSV
  • pydantic-ai, PyPI1.103.0OSV
  • pydantic-ai, PyPI1.104.0OSV
  • pydantic-ai, PyPI1.105.0OSV
  • pydantic-ai, PyPI1.106.0OSV
  • pydantic-ai, PyPI1.107.0OSV
  • pydantic-ai, PyPI1.107.1OSV
  • pydantic-ai, PyPI1.77.0OSV
  • pydantic-ai, PyPI1.78.0OSV
  • pydantic-ai, PyPI1.79.0OSV
  • pydantic-ai, PyPI1.80.0OSV
  • pydantic-ai, PyPI1.81.0OSV
  • pydantic-ai, PyPI1.82.0OSV
  • pydantic-ai, PyPI1.83.0OSV
  • pydantic-ai, PyPI1.84.0OSV
  • pydantic-ai, PyPI1.84.1OSV
  • pydantic-ai, PyPI1.85.0OSV
  • pydantic-ai, PyPI1.85.1OSV
  • pydantic-ai, PyPI1.86.0OSV
  • pydantic-ai, PyPI1.86.1OSV
  • pydantic-ai, PyPI1.87.0OSV
  • pydantic-ai, PyPI1.88.0OSV
  • pydantic-ai, PyPI1.89.0OSV
  • pydantic-ai, PyPI1.89.1OSV
  • pydantic-ai, PyPI1.90.0OSV
  • pydantic-ai, PyPI1.91.0OSV
  • pydantic-ai, PyPI1.92.0OSV
  • pydantic-ai, PyPI1.93.0OSV
  • pydantic-ai, PyPI1.94.0OSV
  • pydantic-ai, PyPI1.95.0OSV
  • pydantic-ai, PyPI1.95.1OSV
  • pydantic-ai, PyPI1.96.0OSV
  • pydantic-ai, PyPI1.96.1OSV
  • pydantic-ai, PyPI1.97.0OSV
  • pydantic-ai, PyPI1.98.0OSV
  • pydantic-ai, PyPI1.99.0OSV
  • pydantic-ai, PyPIfrom 2.0.0b1, fixed in 2.24.0OSV
  • pydantic-ai, PyPI2.0.0OSV
  • pydantic-ai, PyPI2.0.0b1OSV
  • pydantic-ai, PyPI2.0.0b2OSV
  • pydantic-ai, PyPI2.0.0b3OSV
  • pydantic-ai, PyPI2.0.0b4OSV
  • pydantic-ai, PyPI2.0.0b5OSV
  • pydantic-ai, PyPI2.0.0b6OSV
  • pydantic-ai, PyPI2.0.0b7OSV
  • pydantic-ai, PyPI2.1.0OSV
  • pydantic-ai, PyPI2.10.0OSV
  • pydantic-ai, PyPI2.11.0OSV
  • pydantic-ai, PyPI2.12.0OSV
  • pydantic-ai, PyPI2.13.0OSV
  • pydantic-ai, PyPI2.14.0OSV
  • pydantic-ai, PyPI2.14.1OSV
  • pydantic-ai, PyPI2.15.0OSV
  • pydantic-ai, PyPI2.16.0OSV
  • pydantic-ai, PyPI2.17.0OSV
  • pydantic-ai, PyPI2.18.0OSV
  • pydantic-ai, PyPI2.19.0OSV
  • pydantic-ai, PyPI2.2.0OSV
  • pydantic-ai, PyPI2.20.0OSV
  • pydantic-ai, PyPI2.21.0OSV
  • pydantic-ai, PyPI2.22.0OSV
  • pydantic-ai, PyPI2.23.0OSV
  • pydantic-ai, PyPI2.3.0OSV
  • pydantic-ai, PyPI2.4.0OSV
  • pydantic-ai, PyPI2.5.0OSV
  • pydantic-ai, PyPI2.5.1OSV
  • pydantic-ai, PyPI2.6.0OSV
  • pydantic-ai, PyPI2.7.0OSV
  • pydantic-ai, PyPI2.8.0OSV
  • pydantic-ai, PyPI2.9.0OSV
  • pydantic-ai, PyPI2.9.1OSV
  • pydantic-ai-slim, PyPIfrom 1.77.0, fixed in 1.107.2OSV
  • pydantic-ai-slim, PyPI1.100.0OSV
  • pydantic-ai-slim, PyPI1.101.0OSV
  • pydantic-ai-slim, PyPI1.102.0OSV
  • pydantic-ai-slim, PyPI1.103.0OSV
  • pydantic-ai-slim, PyPI1.104.0OSV
  • pydantic-ai-slim, PyPI1.105.0OSV
  • pydantic-ai-slim, PyPI1.106.0OSV
  • pydantic-ai-slim, PyPI1.107.0OSV
  • pydantic-ai-slim, PyPI1.107.1OSV
  • pydantic-ai-slim, PyPI1.77.0OSV
  • pydantic-ai-slim, PyPI1.78.0OSV
  • pydantic-ai-slim, PyPI1.79.0OSV
  • pydantic-ai-slim, PyPI1.80.0OSV
  • pydantic-ai-slim, PyPI1.81.0OSV
  • pydantic-ai-slim, PyPI1.82.0OSV
  • pydantic-ai-slim, PyPI1.83.0OSV
  • pydantic-ai-slim, PyPI1.84.0OSV
  • pydantic-ai-slim, PyPI1.84.1OSV
  • pydantic-ai-slim, PyPI1.85.0OSV
  • pydantic-ai-slim, PyPI1.85.1OSV
  • pydantic-ai-slim, PyPI1.86.0OSV
  • pydantic-ai-slim, PyPI1.86.1OSV
  • pydantic-ai-slim, PyPI1.87.0OSV
  • pydantic-ai-slim, PyPI1.88.0OSV
  • pydantic-ai-slim, PyPI1.89.0OSV
  • pydantic-ai-slim, PyPI1.89.1OSV
  • pydantic-ai-slim, PyPI1.90.0OSV
  • pydantic-ai-slim, PyPI1.91.0OSV
  • pydantic-ai-slim, PyPI1.92.0OSV
  • pydantic-ai-slim, PyPI1.93.0OSV
  • pydantic-ai-slim, PyPI1.94.0OSV
  • pydantic-ai-slim, PyPI1.95.0OSV
  • pydantic-ai-slim, PyPI1.95.1OSV
  • pydantic-ai-slim, PyPI1.96.0OSV
  • pydantic-ai-slim, PyPI1.96.1OSV
  • pydantic-ai-slim, PyPI1.97.0OSV
  • pydantic-ai-slim, PyPI1.98.0OSV
  • pydantic-ai-slim, PyPI1.99.0OSV
  • pydantic-ai-slim, PyPIfrom 2.0.0b1, fixed in 2.24.0OSV
  • pydantic-ai-slim, PyPI2.0.0OSV
  • pydantic-ai-slim, PyPI2.0.0b1OSV
  • pydantic-ai-slim, PyPI2.0.0b2OSV
  • pydantic-ai-slim, PyPI2.0.0b3OSV
  • pydantic-ai-slim, PyPI2.0.0b4OSV
  • pydantic-ai-slim, PyPI2.0.0b5OSV
  • pydantic-ai-slim, PyPI2.0.0b6OSV
  • pydantic-ai-slim, PyPI2.0.0b7OSV
  • pydantic-ai-slim, PyPI2.1.0OSV
  • pydantic-ai-slim, PyPI2.10.0OSV
  • pydantic-ai-slim, PyPI2.11.0OSV
  • pydantic-ai-slim, PyPI2.12.0OSV
  • pydantic-ai-slim, PyPI2.13.0OSV
  • pydantic-ai-slim, PyPI2.14.0OSV
  • pydantic-ai-slim, PyPI2.14.1OSV
  • pydantic-ai-slim, PyPI2.15.0OSV
  • pydantic-ai-slim, PyPI2.16.0OSV
  • pydantic-ai-slim, PyPI2.17.0OSV
  • pydantic-ai-slim, PyPI2.18.0OSV
  • pydantic-ai-slim, PyPI2.19.0OSV
  • pydantic-ai-slim, PyPI2.2.0OSV
  • pydantic-ai-slim, PyPI2.20.0OSV
  • pydantic-ai-slim, PyPI2.21.0OSV
  • pydantic-ai-slim, PyPI2.22.0OSV
  • pydantic-ai-slim, PyPI2.23.0OSV
  • pydantic-ai-slim, PyPI2.3.0OSV
  • pydantic-ai-slim, PyPI2.4.0OSV
  • pydantic-ai-slim, PyPI2.5.0OSV
  • pydantic-ai-slim, PyPI2.5.1OSV
  • pydantic-ai-slim, PyPI2.6.0OSV
  • pydantic-ai-slim, PyPI2.7.0OSV
  • pydantic-ai-slim, PyPI2.8.0OSV
  • pydantic-ai-slim, PyPI2.9.0OSV
  • pydantic-ai-slim, PyPI2.9.1OSV

References 8