Chainlit before 2.10.1 contains a session hijacking vulnerability that allows unauthenticated attackers to restore and inherit authenticated user sessions by presenting a valid sessionId during WebSocket session restoration without ownership verification. Attackers can exploit the restore_existing_session path to assume a victim's permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim.

Metrics

Attack Vector Network

Attack Complexity High

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact High

Subsequent System Integrity Impact High

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required Low

Scope Changed

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact total

Affected Vendors & Products

Vendors Products
Chainlit
  • Chainlit

No data.

No data.

References
Link Providers
https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f cve-icon
https://github.com/Chainlit/chainlit/pull/2857 cve-icon
https://github.com/Chainlit/chainlit/releases/tag/2.10.1 cve-icon
https://www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration cve-icon
History

Tue, 14 Jul 2026 21:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:chainlit:chainlit:*:*:*:*:*:*:*:*

Tue, 23 Jun 2026 15:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}

cvssV4_0

{'score': 9.1, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}

 cvssV3_1

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

cvssV4_0

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

Mon, 22 Jun 2026 18:00:00 +0000

Type Values Removed Values Added
First Time appeared Chainlit
Chainlit chainlit
Vendors & Products Chainlit
Chainlit chainlit

Mon, 22 Jun 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Mon, 22 Jun 2026 15:45:00 +0000

Type Values Removed Values Added
Description Chainlit before 2.10.1 contains a session hijacking vulnerability that allows unauthenticated attackers to restore and inherit authenticated user sessions by presenting a valid sessionId during WebSocket session restoration without ownership verification. Attackers can exploit the restore_existing_session path to assume a victim's permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim.
Title Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration
Weaknesses CWE-862
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}

cvssV4_0

{'score': 9.1, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-06-22T14:17:52.640Z

Updated: 2026-07-14T21:34:00.565Z

Reserved: 2026-06-18T19:15:10.650Z

Link: CVE-2026-56104

cve-icon Vulnrichment

Updated: 2026-06-22T16:06:44.839Z

cve-icon NVD

No data.

cve-icon Redhat

No data.