CVE-2026-56104 | Chainlit before 2.10.1 contains a session hijacking vulnerab… | CVSS 7.4 HIGH

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.

Metadata

CVE ID: CVE-2026-56104
State: PUBLISHED
Assigner: VulnCheck
Reserved: 2026-06-18 19:15 UTC
Published: 2026-06-22 14:17 UTC
Last updated: 2026-06-22 16:06 UTC
Primary CWE: CWE-862
Missing Authorization
Vendor / Product: Chainlit / chainlit
Sources: cve.org · NVD

Severity & Metrics

7.4 HIGH CVSS 3.1

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: total

Affected products (1)

Vendor	Product	Platform	Versions
Chainlit	chainlit	—	0 < 2.10.1

Weakness (CWE)

CWE	Source	Description
CWE-862	cna	Missing Authorization

CVSS scores (2)

Score	Severity	Version	Source	Vector
9.1	CRITICAL	4.0	cna	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
7.4	HIGH	3.1	cna	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References (4)