No VulnCrest analysis published for this CVE yet. Below is the original CNA/NVD description, unmodified.
Description
Chainlit 2.12.0 contains a server-side request forgery vulnerability that allows unauthenticated attackers to bypass path-scoped MCP allowed_urls entries because validate_mcp_url does not reject the semicolon character. Attackers can submit MCP URLs with '..;' segments to the /mcp endpoint, causing requests to paths outside the operator's grant on origins that strip semicolon path parameters.
Exploits & detection
No public PoC or detection template found yet.
Timeline
- Published: 02 Nov 2026
- Last modified upstream: 07 Nov 2026
Sources & licenses
- CVE / CVSS / CWE
- NVD record ↗ (unmodified). This product uses the NVD API but is not endorsed or certified by the NVD. CVE® © The MITRE Corporation.
- Exploitation
- CISA KEV (CC0) · EPSS by FIRST.org
- References used for the analysis
- https://github.com/Chainlit/chainlit/blob/2.12.0/backend/chainlit/mcp.py#L199-L208
- https://github.com/Chainlit/chainlit/blob/2.12.0/backend/chainlit/mcp.py#L90-L177
- https://github.com/Chainlit/chainlit/security/advisories/GHSA-hvfh-5mj3-5f3j
- https://www.vulncheck.com/advisories/chainlit-2.12.0-ssrf-via-semicolon-path-segment-in-mcp-allowed-urls
- https://github.com/Chainlit/chainlit/security/advisories/GHSA-hvfh-5mj3-5f3j
- Analysis, summary and remediation
- © VulnCrest