This page tracks the Ubuntu fix status. The vulnerability itself is described on the main CVE page. View CVE-2026-63383 →

UBUNTU-CVE-2026-63383

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c w...

Original description

The description as published by the source.

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c when decode_tag_internal requests at most five bytes from evbuffer_pullup but iterates using the full logical buffer length. A fragmented evbuffer containing a six-byte malformed tag can therefore advance past the pullup window and trigger an out-of-bounds read, which can crash a process that decodes attacker-controlled tagged RPC data. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Source: OSV.dev (Open Source Vulnerabilities) OSV

Affected packages

Ubuntu:Pro:14.04:LTS libevent

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.21-stable-1ubuntu1.14.04.2+esm1"}]}]

Ubuntu:Pro:16.04:LTS libevent

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.21-stable-2ubuntu0.16.04.1+esm1"}]}]

Ubuntu:Pro:18.04:LTS libevent

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.8-stable-4ubuntu0.1~esm1"}]}]

Ubuntu:Pro:20.04:LTS libevent

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.11-stable-1ubuntu0.1~esm1"}]}]

Ubuntu:22.04:LTS libevent

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.12-stable-1ubuntu0.1"}]}]

Ubuntu:24.04:LTS libevent

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.12-stable-9ubuntu2.1"}]}]

Ubuntu:26.04:LTS libevent

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.12-stable-10ubuntu0.1"}]}]

References

advisory ubuntu.com
report ubuntu.com
report cve.org