Integer Overflow or Wraparound Affecting libevent package, versions <2.1.8-stable-4ubuntu0.1~esm1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.52% (42nd percentile)

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  • Snyk IDSNYK-UBUNTU1804-LIBEVENT-19169787
  • published2 Sept 2026
  • disclosed20 Aug 2026

Introduced: 20 Aug 2026

CVE-2026-63384  (opens in a new tab)
CWE-190  (opens in a new tab)

How to fix?

Upgrade Ubuntu:18.04 libevent to version 2.1.8-stable-4ubuntu0.1~esm1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libevent package and not the libevent package as distributed by Ubuntu. See How to fix? for Ubuntu:18.04 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1