Bug 2544592 - CVE-2026-57585 borgbackup: MessagePack for Python: Denial of Service via Unpacker reuse after error [epel-all]
Summary: CVE-2026-57585 borgbackup: MessagePack for Python: Denial of Service via Unpa...
Keywords:
Status: ASSIGNED
Alias: None
Product: Fedora EPEL
Classification: Fedora
Component: borgbackup
Version: epel8
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: ---
Assignee: Felix Schwarz
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["49a30b0f-ca41-47e7-b653-d...
Depends On:
Blocks: CVE-2026-57585
TreeView+ depends on / blocked
 
Reported: 2026-10-01 11:36 UTC by Tomas Hoger
Modified: 2026-10-03 11:20 UTC (History)
1 user (show)

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

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Description Tomas Hoger 2026-10-01 11:36:59 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.

MessagePack is the serializer implementation for Python msgpack.org. Prior to 1.2.1, there is an Out-of-bounds read/crash on Unpacker reuse after a caught error, potentially leading to a DoS attack.  If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. This issue has been fixed in version 1.2.1.
Comment 1 Felix Schwarz 2026-10-03 11:20:19 UTC 
This issue should be about EPEL 8 which bundles an older version of msgpack.

EPEL 9+10 use whatever msgpack is provided by the system (though we need to patch borgbackup to accept the latest msgpack 1.2.3).

Upstream support for msgpack 1.2.3 in borgbackup 1.4.x: https://github.com/borgbackup/borg/commit/084f3fbce66c29334ad0a1d83324011398339547
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