How severe is CVE-2026-59821?

No CVSS score has been assigned to CVE-2026-59821 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-59821?

CVE-2026-59821 affects the following packages: litellm (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-59821?

Update litellm to 1.82.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-59821 is resolved across your whole dependency graph.

How do I detect CVE-2026-59821 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for litellm, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-59821 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2026-59821 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-59821 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-59821?

CVE-2026-59821 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 59th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-59821?

CVE-2026-59821 is classified as Code Injection (CWE-94). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-59821 published, and has it been updated?

CVE-2026-59821 was published on July 8, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-59821 — litellm

Fix: BerriAI/litellm@e50b448

CVE-2026-59821 is a Code Injection vulnerability in litellm. A fix is available for litellm — see the affected versions and patch details below.

LiteLLM: Custom Code Guardrails production endpoints bypass code safety checks

Also known asGHSA-72m8-9m7m-h278PYSEC-2026-3478

Published

Jul 8, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 19, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-59821.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍litellm

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

LiteLLM's Custom Code Guardrails production create/update paths did not apply the same sandboxing and validation used by the test endpoint.

A privileged user with access to create or update guardrails could submit custom Python code that executed in the LiteLLM proxy environment. In deployments without a configured master key, callers could be treated as proxy administrators, making this reachable without intended administrative authorization.

This could allow arbitrary code execution in the LiteLLM proxy container and exposure of secrets available to the process.

Patches

The issue is fixed in 1.82.0-stable.

LiteLLM recommend upgrading to 1.82.0-stable or later.

Workarounds

If upgrading is not immediately possible:

Restrict access to POST /guardrails and PUT /guardrails/{guardrail_id} to trusted administrators only.
Ensure LITELLM_MASTER_KEY is configured.
Avoid enabling Custom Code Guardrails for untrusted users.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`litellm`	all versions	1.82.0`pip install --upgrade 'litellm==1.82.0'`

Affected Products

1 product · 2 configurations

Application

litellmlitellm

< 1.82.0

1 version

1.82.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for litellm, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update litellm to 1.82.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-59821 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

Red Hat rates this flaw with higher severity than the upstream GitHub Security Advisory (GHSA-72m8-9m7m-h278, CVSS v4.0 2.1, Low). Red Hat scored this CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H (7.2, Important) because a successful exploit grants arbitrary Python code execution within the LiteLLM proxy process,…

Workaround published by Red Hat

Upgrade litellm to 1.82.0 or later, which enforces the same code-safety checks on the guardrail create/update endpoints as the test endpoint. If upgrading is not immediately possible, restrict access to POST /guardrails and PUT /guardrails/{guardrail_id} to trusted administrators only, ensure LITELLM_MASTER_KEY is configured so unauthenticated callers are not treated as proxy administrators, and avoid enabling Custom Code Guardrails for untrusted users.

Source: Red Hat security advisory for CVE-2026-59821 (CC BY 4.0)

Frequently Asked Questions

### Impact LiteLLM's Custom Code Guardrails production create/update paths did not apply the same sandboxing and validation used by the test endpoint. A privileged user with access to create or update guardrails could submit custom Python code that executed in the LiteLLM proxy environment. In deployments without a configured master key, callers could be treated as proxy administrators, making this reachable without intended administrative authorization. This could allow arbitrary code execution in the LiteLLM proxy container and exposure of secrets available to the process. ### Patches T

O3 Security · Impact-Aware SCA

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