CVE-2026-63380Public exploit

Process crash via uninserted WebSocket session removal

Published Aug 20, 2026 · Updated Aug 25, 2026

NULL pointer dereference in Libevent before 2.2.2-alpha allows local users to crash a host process through the WebSocket API. The evws_new_session error path calls evws_connection_free after locking fails, and TAILQ_REMOVE dereferences list pointers for a session never inserted into ws_sessions. Triggering the crash requires a local caller to induce an allocation or locking failure; the reachable impact is process termination, while the reported use-after-free is not reachable.

CVSS severity5.7
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Libevent before 2.2.2-alpha allows local users to crash a host process through the WebSocket API. The evws_new_session error path calls evws_connection_free after locking fails, and TAILQ_REMOVE dereferences list pointers for a session never inserted into ws_sessions. Triggering the crash requires a local caller to induce an allocation or locking failure; the reachable impact is process termination, while the reported use-after-free is not reachable.

The record

CVE
CVE-2026-63380
Published
Aug 20, 2026
Updated
Aug 25, 2026
Vendor
Libevent
Product
Libevent
Classifications
CWE-476, CWE-416, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.2.2-alpha

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Libevent · Libeventversion=< 2.2.2-alpha

Published CVSS scores

5.7GitHub Security AdvisoryCVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
CWE-416Use After Free
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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