CVE-2026-42271

HIGH CISA KEV EPSS 99.4%
Published May 8, 20261mo ago · Modified Jun 17, 20261w ago
8.7 CVSS 4.0
High
Find Similar
Published May 8, 2026 1mo ago
Last Modified Jun 17, 2026 1w ago
KEV Listed Jun 8, 2026 3w ago
KEV Due Jun 22, 2026 8d overdue

Description

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.

CVSS Details

Base Score
8.7
Exploitability
—
Impact
—
Vector string
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
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope X

Threat Intelligence

CISA Known Exploited Overdue 8d
Added
Jun 8, 2026
Due
Jun 22, 2026

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

EPSS Exploit Probability
99.4% percentile
Exploit & Patch Status
Actively Exploited (KEV)
Patch Available

Weaknesses 2

CWE-77 Command Injection Injection
CWE-78 OS Command Injection Injection

Affected Products 1

VendorProductVersionRange
litellmlitellm*≥1.74.2  –  <1.83.7

References 3

  • github.com https://github.com/BerriAI/litellm/releases/tag/v1.83.7-stable
    ProductRelease Notes
  • github.com https://github.com/BerriAI/litellm/security/advisories/GHSA-v4p8-mg3p-g94g
    MitigationPatchVendor Advisory
  • cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-42271
    US Government Resource

Remediation

  • github.com https://github.com/BerriAI/litellm/security/advisories/GHSA-v4p8-mg3p-g94g
    MitigationPatchVendor Advisory