CVE-2026-42271
CWE-77Published: May 8, 2026· Updated: May 8, 2026
Official 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.
Technical Analysis
CVE-2026-42271 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.
CISA has added CVE-2026-42271 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
News & Research Mentioning CVE-2026-42271
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Monday added a high-severity flaw impacting BerriAI LiteLLM to its Known Exploited Vulnerabilities (KEV) catalog, citing evidence of active exploitation. The vulnerability, tracked as CVE-2026-42271 (CVSS score: 8.7), is a command injection vulnerability that could allow any authenticated user to run arbitrary commands on the [xlite_meta score:53 src:The Hacker News xlite_fp:271a994140e18a2075dda169425fb8c761ca989d288f9cc1cbde736501803dda]
CISA has added two new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2026-42271 BerriAI LiteLLM Command Injection Vulnerability CVE-2026-50751 Check Point Security Gateway Improper Authentication Vulnerability These types of vulnerabilities are a frequent attack vector for malicious cyber actors and pose significant risks to the federal enterprise. Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities established the KEV Catalog as a living list of known Common Vulnerabilities and Exposures (CVEs) that carry significant risk to the federal enterprise. BOD 22-01 requires Federal Civilian Executive Branch (FCEB) agencies to remedi [xlite_meta score:51 src:CISA Alerts xlite_fp:112ecae3057d58d0b590d4b4cf769408b4f5d887d2a23eae3f44dd31a01b3dc6]
All References (2)
Quick Facts
Related CVEs (CWE-77)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-42271 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1