CVE-2026-56104

Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration

HIGH
8.2
CVSS Score
Published: June 22, 2026 at 02:17 PM UTC
Updated: October 8, 2026 at 04:17 PM UTC
1 product affected across 1 vendorChainlit

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Severity
HIGH8.2
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0 ≤ v < 2.10.10
Affected range stops below 2.10.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.2HIGHVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-862

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