CVE-2026-63380

What it is

Libevent is an event notification library. Prior to 2.2.2-alpha, libevent can dereference invalid list pointers in ws.c when evws_new_session enters its error path after evhttp_start_ws_ succeeds but bufferevent_enable_locking_ fails. evws_connection_free sees a non-null http_server and unconditionally calls TAILQ_REMOVE even though the session was never inserted into http_server->ws_sessions. A local caller able to induce this allocation or locking failure can crash the process. This issue is fixed in version 2.2.2-alpha.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

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

Timeline

1. 2026-08-20 18:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-26 10:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.1% in the next 30 days (EPSS).
• Severity: 5.7 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-08-20 18:16 UTC

Last modified

2026-10-26 10:10 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-416 · Use after free

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 5.7

Attack vector

Local

Complexity

High

Attack requirements

Present

Privileges needed

Low

User interaction

None

Confidentiality

None

Integrity

None

Availability

High

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-2026-63380.md and follow it. Check whether this project is affected by CVE-2026-63380. 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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