How severe is CVE-2026-12773?

CVE-2026-12773 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-12773 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-12773?

CVE-2026-12773 affects Litellm. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-12773?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-12773 have an EU (EUVD) identifier?

Yes. CVE-2026-12773 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38139.

When was CVE-2026-12773 published?

CVE-2026-12773 was published on 2026-06-21 and last updated on 2026-06-30.

CVE-2026-12773

CVE-2026-12773 is a high-severity vulnerability in Litellm with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 3.x base score 7.3)
CVSS v2: 7.5
CVSS v4: 5.5
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38139
Weakness: CWE-287
Affected product: Litellm
Published: 2026-06-21
Last modified: 2026-06-30

Description

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.

Frequently asked questions

What is CVE-2026-12773?: 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.
How severe is CVE-2026-12773?: CVE-2026-12773 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-12773 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-12773?: CVE-2026-12773 affects Litellm. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-12773?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-12773 have an EU (EUVD) identifier?: Yes. CVE-2026-12773 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38139.
When was CVE-2026-12773 published?: CVE-2026-12773 was published on 2026-06-21 and last updated on 2026-06-30.

References

Affected products (1)

cpe:2.3:a:litellm:litellm:*:*:*:*:*:*:*:*

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