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.
History

Sat, 07 Nov 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 02 Nov 2026 14:30:00 +0000

Type Values Removed Values Added
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.
Title Chainlit 2.12.0 SSRF via Semicolon Path Segment in MCP allowed_urls
First Time appeared Chainlit
Chainlit chainlit
Weaknesses CWE-918
CPEs cpe:2.3:a:chainlit:chainlit:2.12.0:*:*:*:*:*:*:*
Vendors & Products Chainlit
Chainlit chainlit
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N'}

cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-11-02T14:29:20.711Z

Updated: 2026-11-07T00:22:59.156Z

Reserved: 2026-11-02T14:15:21.510Z

Link: CVE-2026-120492

cve-icon Vulnrichment

Updated: 2026-11-07T00:22:51.951Z

cve-icon NVD

Status : Deferred

Published: 2026-11-02T15:17:31.210

Modified: 2026-11-07T01:17:02.410

Link: CVE-2026-120492

cve-icon Redhat

No data.