Vulnerability in pydantic-ai (CVE-2026-107294)
Summary
Vulnerability in pydantic-ai (CVE-2026-107294). Risk of unauthorized operations or information disclosure. Exploitable via web_fetch_tool. Mitigation: upgrade to 2.24.0 or later.
Original description
The description as published by the source.
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 versio…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-107294 has been found in pydantic-ai.
Attackers can target a specific entry point like web_fetch_tool over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: upgrade pydantic-ai to 2.24.0 or later.
If unsure, ask your IT team or search "pydantic-ai CVE-2026-107294" on the vendor's site.
CVE-2026-107294 (pydantic-ai) — CWE-400 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: web_fetch_tool / WebFetch / FileUrl / ImageUrl
Patched: 2.24.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-400) exists in pydantic-ai. Attackers reach the vulnerable code path via web_fetch_tool.
Check the vendor advisory for the affected versions of pydantic-ai. Attack surface: web_fetch_tool / WebFetch / FileUrl / ImageUrl.
Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.
Update to 2.24.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'pydantic-ai' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'pydantic-ai' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
pydantic-aiを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade pydantic-ai to 2.24.0ステージング環境で 2.24.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- package pypi.org
- package pypi.org
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com