Bug 2520657 (CVE-2026-63381) - CVE-2026-63381 libevent: Libevent: Memory corruption due to use-after-free
Summary: CVE-2026-63381 libevent: Libevent: Memory corruption due to use-after-free
Keywords:
Status: NEW
Alias: CVE-2026-63381
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2527797
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-20 18:05 UTC by OSIDB Bzimport
Modified: 2026-09-22 13:00 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2026:68390 0 None None None 2026-09-16 21:24:01 UTC
Red Hat Product Errata RHBA-2026:68772 0 None None None 2026-09-17 20:46:20 UTC
Red Hat Product Errata RHBA-2026:69286 0 None None None 2026-09-21 11:12:00 UTC
Red Hat Product Errata RHBA-2026:69411 0 None None None 2026-09-21 13:52:56 UTC
Red Hat Product Errata RHBA-2026:69920 0 None None None 2026-09-22 08:29:59 UTC
Red Hat Product Errata RHBA-2026:70231 0 None None None 2026-09-22 13:00:28 UTC
Red Hat Product Errata RHSA-2026:67909 0 None None None 2026-09-16 11:48:37 UTC
Red Hat Product Errata RHSA-2026:67910 0 None None None 2026-09-16 12:59:43 UTC

Description OSIDB Bzimport 2026-08-20 18:05:04 UTC 
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len is zero. evbuffer_free_all_chains frees the initial empty chain without resetting outbuf->first, outbuf->last, or outbuf->last_with_datap, and APPEND_CHAIN_MULTICAST subsequently dereferences the dangling chain pointer. A caller that can drive this buffer state can cause memory corruption or a process crash. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
Comment 2 Jon Orris 2026-09-16 11:48:35 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:67909 https://access.redhat.com/errata/RHSA-2026:67909
Comment 3 Jon Orris 2026-09-16 12:59:41 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:67910 https://access.redhat.com/errata/RHSA-2026:67910
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