---
id: CVE-2026-63380
title: Libevent is an event notification library
summary: >-
  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. ev…
severity: medium
cwe:
  - CWE-416
  - CWE-476
published: '2026-08-20'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:19:49.197'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63380'
references:
  - url: >-
      https://github.com/libevent/libevent/commit/825c18bd99f556b59d61200523237f264d5cc734
    label: security-advisories@github.com
  - url: 'https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha'
    label: security-advisories@github.com
  - url: >-
      https://github.com/libevent/libevent/security/advisories/GHSA-3rpf-frgx-xq34
    label: security-advisories@github.com
  - url: >-
      https://github.com/libevent/libevent/security/advisories/GHSA-3rpf-frgx-xq34
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63380.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-63380'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2520656'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-63380'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63380'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.0014
epssPercentile: 0.02752
ingestedAt: '2026-09-09T21:22:45.544Z'
vendor: Red Hat
product: Red Hat Enterprise Linux 6
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 7
  - enterprise_linux 8
  - openshift_container_platform 4
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63380.json)