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Response snapshot Oct 26, 2026, 22:02 UTC

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VulnerabilityCVE-2026-114386

Pydantic AI Harness tool-call limit bypass in nested CodeMode calls

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.

At a glance

Exploited
Not known
Severity
6.3 Medium (CVSS 4.0)
Chance of exploitation
0.3% in the next 30 days
Sources
1 source

What to do

GitHub lists first patched versions: pydantic-ai-harness: 0.59.0. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-3589-pxp7-3gj8 (opens a new tab)

What happened

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 package ranges reported by GitHub: pydantic-ai-harness: < 0.59.0

Scores and how they were measured

CVSS base severity

6.3

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.3%

Scored Percentile 28.0%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-3589-pxp7-3gj8 (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-3589-pxp7-3gj8, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  3. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-114386, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 23). Pydantic AI Harness tool-call limit bypass in nested CodeMode calls (CVE-2026-114386). https://kevwire.com/record/CVE-2026-114386

MLA

"Pydantic AI Harness tool-call limit bypass in nested CodeMode calls (CVE-2026-114386)." KEVWire, 23 Oct. 2026, kevwire.com/record/CVE-2026-114386.

Chicago

KEVWire. "Pydantic AI Harness tool-call limit bypass in nested CodeMode calls (CVE-2026-114386)." Last modified October 23, 2026. https://kevwire.com/record/CVE-2026-114386.

Evidence summary (plain text)

Pydantic AI Harness tool-call limit bypass in nested CodeMode calls (Oct 21, 2026).
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.
CVSS 6.3 (version 4.0; evidence as of Oct 23, 2026; https://github.com/advisories/GHSA-3589-pxp7-3gj8).
EPSS 0.3% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-114386&date=2026-10-26).
Sources:
GitHub-reviewed advisory GHSA-3589-pxp7-3gj8: https://github.com/advisories/GHSA-3589-pxp7-3gj8
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-114386&date=2026-10-26
Record ID: CVE-2026-114386.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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