Description
Chainlit through 2.12.0 fails to validate the client-supplied socket.io sessionId parameter, allowing unauthenticated attackers to traverse filesystem paths by injecting absolute or relative path sequences. Attackers can craft malicious sessionId values that escape the upload directory and recursively delete arbitrary directories accessible to the service process.
Published: 2026-09-09
Score: 8.8 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Wed, 09 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 09 Sep 2026 13:45:00 +0000

Type Values Removed Values Added
Description Chainlit through 2.12.0 fails to validate the client-supplied socket.io sessionId parameter, allowing unauthenticated attackers to traverse filesystem paths by injecting absolute or relative path sequences. Attackers can craft malicious sessionId values that escape the upload directory and recursively delete arbitrary directories accessible to the service process.
Title Chainlit through 2.12.0 Path Traversal via socket.io sessionId
First Time appeared Chainlit
Chainlit chainlit
Weaknesses CWE-22
CPEs cpe:2.3:a:chainlit:chainlit:*:*:*:*:*:*:*:*
Vendors & Products Chainlit
Chainlit chainlit
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H'}

cvssV4_0

{'score': 8.8, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N'}


Subscriptions

Chainlit Chainlit
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-09T14:49:36.459Z

Reserved: 2026-09-04T22:51:17.817Z

Link: CVE-2026-86099

cve-icon Vulnrichment

Updated: 2026-09-09T14:47:39.625Z

cve-icon NVD

Status : Received

Published: 2026-09-09T14:17:20.387

Modified: 2026-09-09T15:17:12.453

Link: CVE-2026-86099

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses