Command Injection Vulnerability in Chainlit Framework by Chainlit
CVE-2026-45018

9.8CRITICAL

Key Information:

Vendor

Chainlit

Status
Chainlit
Vendor
CVE Published:
25 August 2026

What is CVE-2026-45018?

The Chainlit Framework versions 2.4.0rc0 to 2.12.0 have a critical vulnerability that allows command injection via an unauthenticated endpoint. When the feature features.mcp.enabled is enabled in .chainlit/config.toml, the /mcp POST endpoint can be exploited by sending a user-controlled fullCommand string. The vulnerability is due to insufficient validation of command parameters, specifically in the validate_mcp_command() function, allowing attackers to execute arbitrary shell commands under the privileges of the Chainlit process. If the allowed_executables list is not configured, any executable can be run, vastly increasing the risk of command injection attacks. This vulnerability has been addressed in version 2.12.0.

Affected Version(s)

chainlit >= 2.4.0rc0, < 2.12.0

References

https://github.com/Chainlit/chainlit/security/advisories/...
x_refsource_CONFIRM
https://github.com/Chainlit/chainlit/commit/0565fd0eccb91...
x_refsource_MISC
https://github.com/Chainlit/chainlit/blob/2.12.0/docs/sec...
x_refsource_MISC

CVSS V3.1

Score:
9.8
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.