CVE-2026-63384: Libevent

High severity, CVSS 8.7. EPSS: 0.5% chance of exploitation in the next 30 days.

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an incorrect integer conversion in event_tagging.c when evtag_unmarshal_header uses evtag_decode_int to decode an attacker-controlled uint32 payload length and returns it as a signed int. Values above INT_MAX become negative or truncated, and evtag_unmarshal_string can use the converted value in allocation sizing, producing a wrapped large allocation request and denial of service. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Affected products

• Libevent Libevent: from 2.2.0-alpha, before 2.2.2-alpha (fixed in 2.2.2-alpha); before 2.1.13 (fixed in 2.1.13)

Published 2026-08-20. Last modified 2026-09-09.