CVE-2026-12773: A weakness has been identified in BerriAI litellm up to 1.59.8

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HIGH 7.3REMOTEUPGRADE

CVE-2026-12773 is a high-severity flaw (CVSS 7.3) affecting litellm. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A weakness has been identified in BerriAI litellm up to 1.59.8. Affected is the function UserAPIKeyAuth of the file litellm/proxy/_experimental/mcp_server/auth/user_api_key_auth_mcp.py of the component MCP Proxy. Executing a manipulation can lead to improper authentication. The attack may be launched remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 37%)
CISA exploited list	No
Weakness	CWE-287, CWE-303
Published	2026-06-21
Last modified	2026-10-25

Publisher (CNA): VulDB · Vendor: litellm

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-21 04:16 UTCPublished CVE record published
2026-10-25 23:10 UTCUpdated Record last modified

litellm litellm UPGRADE

Affected: < 1.59.9

Fixed in: 1.59.9

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy litellm || rpm -q litellm || litellm --version

2. UPGRADE to 1.59.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade litellm

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade litellm

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Python (pip) · litellm · FIXED · 1.84.0 · vulnerable: < 1.84.0 · source

pip install --upgrade "litellm>=1.84.0" pip show litellm

Fedora 46 · rust-opendal-core · FIXED · 0.59.1-2.fc46 · FEDORA-2026-4607543819 · source

sudo dnf upgrade --advisory=FEDORA-2026-4607543819

Fedora ELN · velocitty · FIXED · 1.0.3-2.eln159 · FEDORA-2026-edae8cd295 · source

sudo dnf upgrade --advisory=FEDORA-2026-edae8cd295

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: gist.github.com/YLChen-007/3cfaad10a69d7a15e4d4d458cb53309e

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-12773?

litellm: upgrade to 1.59.9. Exact commands for each OS are on this page.

Is CVE-2026-12773 being exploited?

CVE-2026-12773 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-12773 affect?

CVE-2026-12773 affects litellm. Severity is high (CVSS 7.3). A weakness has been identified in BerriAI litellm up to 1.59.8. Affected is the function UserAPIKeyAuth of the file litellm/proxy/_experimental/mcp_server/auth/user_api_key_auth_mcp.py of the component MCP Proxy. Executing a manipulation ca

How urgent is CVE-2026-12773?

Priority 51/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-49468 CRITICAL 9.8 UPGRADE LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format
CVE-2026-12795 HIGH 7.3 UPGRADE A vulnerability was determined in BerriAI litellm up to 1.82.2
CVE-2026-12796 MEDIUM 6.3 UPGRADE A vulnerability was identified in BerriAI litellm up to 1.82.2
CVE-2026-12770 MEDIUM 5.4 UPGRADE A vulnerability was determined in BerriAI litellm up to 1.63.1
CVE-2026-12772 MEDIUM 6.3 UPGRADE A security flaw has been discovered in BerriAI litellm up to 1.82.2

References

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