Bug 2527797

Summary:	CVE-2026-63381 libevent: Libevent: Memory corruption due to use-after-free [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Laura Pardo <lpardo>
Component:	libevent	Assignee:	Steve Dickson <steved>
Status:	ON_QA ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rawhide	CC:	jorton, pzacik, steved
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["74099a03-c90c-438b-9f89-2f92ec9da514"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2520657

Description Laura Pardo 2026-09-02 21:32:30 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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 1 Fedora Update System 2026-09-07 14:05:40 UTC

FEDORA-2026-0a83f1b852 (libevent-2.1.13-1.fc45) has been submitted as an update to Fedora 45.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-0a83f1b852

Comment 2 Fedora Update System 2026-09-07 14:08:40 UTC

FEDORA-2026-72d10c874d (libevent-2.1.13-1.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-72d10c874d

Comment 3 Fedora Update System 2026-09-07 14:19:54 UTC

FEDORA-2026-728dd9f704 (libevent-2.1.13-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-728dd9f704

Comment 4 Fedora Update System 2026-09-08 01:37:49 UTC

FEDORA-2026-0a83f1b852 has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-0a83f1b852`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-0a83f1b852

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 5 Fedora Update System 2026-09-08 01:57:48 UTC

FEDORA-2026-72d10c874d has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-72d10c874d`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-72d10c874d

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 6 Fedora Update System 2026-09-08 02:20:21 UTC

FEDORA-2026-728dd9f704 has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-728dd9f704`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-728dd9f704

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 7 Fedora Update System 2026-09-09 04:50:59 UTC

FEDORA-2026-72d10c874d (libevent-2.1.13-1.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 8 Fedora Update System 2026-09-11 01:27:19 UTC

FEDORA-2026-728dd9f704 (libevent-2.1.13-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.