CVE-2026-56104

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure, data tampering.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-06-22 16:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-08 16:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 8.8 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-06-22 16:16 UTC

Last modified

2026-10-08 16:17 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-862 · Missing authorization

Record status

Deferred

Attack profile CVSS 4.0 · 8.8

Attack vector

Network

Complexity

High

Attack requirements

None

Privileges needed

Low

User interaction

None

Confidentiality

High

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-56104.md and follow it. Check whether this project is affected by CVE-2026-56104. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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