What’s Vulnerable › Vulnerabilities

CVE-2026-114386: Pydantic AI Harness before 0.59.0 CodeMode Tool Call Limit Bypass via run_code

• Severity: medium (CVSS 4.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-21 · updated 2026-10-22
• Weakness: CWE-770

Description

Pydantic AI Harness before 0.59.0 fails to enforce UsageLimits.tool_calls_limit on nested tool calls dispatched from run_code in the CodeMode toolset. Users or prompt-injected content can make the sandboxed program invoke tools via run_nested_call() without check_before_tool_call, exceeding operator limits on costly or side-effecting tools.

Affected products

• pydantic-ai-harness: before 0.59.0 — fixed in 0.59.0

How to fix

Upgrade to a fixed version: pydantic-ai-harness 0.59.0. Check the vendor advisory for mitigations.

References

• https://github.com/pydantic/pydantic-ai/blob/v2.58.0/src/pydantic_ai_harness/pydantic_ai_harness/code_mode/_toolset.py#L642-L680
• https://github.com/pydantic/pydantic-ai/commit/eb27b2b89fe76ae23ee9b6fc9eb4b227a4967949
• https://github.com/pydantic/pydantic-ai/pull/10362
• https://github.com/pydantic/pydantic-ai/releases/tag/v2.59.0
• https://pypi.org/project/pydantic-ai-harness/0.59.0/
• https://www.vulncheck.com/advisories/pydantic-ai-harness-before-0.59.0-codemode-tool-call-limit-bypass-via-run-code

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