9.1
CRITICAL CVSS 4.0
CVE-2026-56104
Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration
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.

INFO

Published Date :

June 22, 2026, 2:17 p.m.

Last Modified :

June 22, 2026, 2:17 p.m.

Remotely Exploit :

Yes !

Source :

VulnCheck
Affected Products

The following products are affected by CVE-2026-56104 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 CRITICAL 83251b91-4cc7-4094-a5c7-464a1b83ea10
Solution
Update Chainlit to version 2.10.1 or later to fix session hijacking.
  • Update Chainlit to version 2.10.1 or newer.
  • Verify session restoration process includes ownership checks.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-56104 vulnerability anywhere in the article.

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.