litellm: Improper Authentication
CVE-2026-12773 is a critical-severity improper authentication vulnerability in litellm from BerriAI, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected litellm versions: 1.59.0; 1.59.1; 1.59.2, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.02% chance of exploitation within 30 days, higher than 64% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of litellm you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| BerriAI | litellm | 1.59.0; 1.59.1; 1.59.2; 1.59.3; 1.59.4; 1.59.5; 1.59.6; 1.59.7; and 1 more ranges | Not stated |
| Red Hat | Exploit Intelligence | Not specified in the record | Not stated |
| Red Hat | Red Hat Ansible Automation Platform 2 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift AI (RHOAI) | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.5 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 7.3 | High | CNA (vuldb.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 3.1 | 7.3 | High | CNA |
| CVSS 2.0 | 7.5 | High | CNA (vuldb.com) |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- vuldb.com/cve/CVE-2026-12773Third Party Advisory, VDB Entry
- vuldb.com/vuln/372515Third Party Advisory, VDB Entry
Technical write-ups (may include proof of concept)
- gist.github.com/YLChen-007/3cfaad10a69d7a15e4d4d458cb53309eExploit, Third Party Advisory
- vuldb.com/submit/811282Exploit, Third Party Advisory, VDB Entry
Other references
Other vulnerabilities in litellm
- 9.9 Critical severity
- 8.1 High severity
- 7.7 High severity
- 8.2 High severity
BerriAI LiteLLM Improper Authentication Exploited
- 7.2 High severity
- 9.8 Critical severity
Recent Improper Authentication vulnerabilities
- 7.3 High severity
- 8.1 High severity
- 8.1 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 9.1 Critical severity
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