CVE-2026-107294
Description
A flaw was found in Pydantic AI. When fetching remote web content or media files, the framework buffers the entire response in memory before enforcing content-size limits. A remote attacker can exploit this issue by supplying a link that streams an excessively large response, exhausting memory and crashing the application worker, resulting in a Denial of Service (DoS).
Statement
A denial of service vulnerability of moderate severity was found in pydantic-ai, a Python agent framework used in Red Hat Enterprise Linux AI and Lightspeed Core products. When fetching remote web content or media files, pydantic-ai buffers the entire HTTP response body in memory before enforcing content-size limits. A remote attacker who can influence a URL processed by an application that exposes pydantic-ai's web-fetch functionality (web_fetch_tool or the WebFetch local fallback) or downloads remote FileUrl media (ImageUrl, DocumentUrl, VideoUrl, AudioUrl) can supply a link that streams an excessively large response, exhausting process memory and crashing the application worker. The impact is limited to availability; SSRF protections remain effective, and there is no confidentiality or integrity impact. Red Hat and upstream both assess this issue as MODERATE severity with a CVSS 3.1 base score of 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Because the impact is moderate with a CVSS score below 7.0, the fix for the affected Red Hat products is deferred and no update trackers are being filed at this time; the residual risk is a denial of service against application workers that process attacker-influenced URLs.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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