ZeusQA
Start free

Known exploited vulnerability

CVE-2026-42271

highCVSS 4.0 8.7In CISA KEVEPSS 91%Published · BerriAI

The short answer

CVE-2026-42271 affects BerriAI litellm and is rated high (CVSS 8.7). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-06-08: attackers are using it, so patch it first. Fixed versions are published for litellm (1.83.7).

What it is

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. From version 1.74.2 to before version 1.83.7, two endpoints used to preview an MCP server before saving it — POST /mcp-rest/test/connection and POST /mcp-rest/test/tools/list — accepted a full server configuration in the request body, including the command, args, and env fields used by the stdio transport. When called with a stdio configuration, the endpoints attempted to connect, which spawned the supplied command as a subprocess on the proxy host with the privileges of the proxy process. The endpoints were gated only by a valid proxy API key, with no role check. Any authenticated user — including holders of low-privilege internal-user keys — could therefore run arbitrary commands on the host. This issue has been patched in version 1.83.7.

Weakness: CWE-77, CWE-78.

Severity

8.7 high

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/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

Exploited (CISA KEV)

Yes, since Jun 8, 2026

Federal due date Jun 22, 2026

EPSS, next 30 days

91%

Higher than 100% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Attack requirements
Present
Privileges required
Low
User interaction
None
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Affected packages and fixed versions

PackageEcosystemFixed inAdvisory
litellmPyPI1.83.7GHSA-v4p8-mg3p-g94g

Is it in your code? Drop your lockfile into the free vulnerability check, or let vulnerability watch check your repository every day and open the upgrade as a pull request.

Affected products

litellm, Red Hat OpenShift AI 2.25, Red Hat OpenShift AI 3.3, Red Hat OpenShift AI 3.4, Exploit Intelligence, Red Hat Ansible Automation Platform 2, Red Hat OpenShift AI (RHOAI). NVD's record lists the exact affected versions.

References

Questions

Is CVE-2026-42271 being exploited?

Yes. CISA added CVE-2026-42271 to its Known Exploited Vulnerabilities catalog on 2026-06-08, with a federal remediation due date of 2026-06-22.

How do I fix CVE-2026-42271?

Upgrade to a fixed version: litellm (PyPI) 1.83.7. CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

Related

Know the day a CVE lands in your code

Connect a GitHub repository and ZeusQA checks its dependencies daily, briefs each advisory and opens the fix. Three test runs free, no card.

Start freeSee how a run works