Medium [CVE-2026-63380] Denial of Service via Null Pointer Dereference
This medium-severity Red Hat Linux advisory covers CVE-2026-63380 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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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. 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.
This vulnerability allows a local attacker to trigger a null pointer dereference during specific error handling within the `evws_new_session` function. By inducing an allocation or locking failure, an attacker can cause the application to crash, leading to a denial of service.
Red Hat severity: Moderate — CVSS 4.7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-476.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Hardened Images; Red Hat OpenShift Container Platform 4. Will not fix / out of support: Red Hat Enterprise Linux 6.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: libevent2.
- < 2.2.2-alpha
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation
Upgrade to a fixed release: 2.2.2. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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