Bug 2544595 - CVE-2026-57585 python-msgpack: MessagePack for Python: Denial of Service via Unpacker reuse after error [fedora-all]
Summary: CVE-2026-57585 python-msgpack: MessagePack for Python: Denial of Service via ...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: python-msgpack
Version: rawhide
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: ---
Assignee: Jonathan Wright
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 11:37 UTC by Tomas Hoger
Modified: 2026-10-03 11:17 UTC (History)
6 users (show)

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

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Description Tomas Hoger 2026-10-01 11:37:34 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 11:17:37 UTC 
If you update msgpack to 1.2.3, please let us coordinate a borgbackup update. I guess I need to cherry-pick an upstream patch because there is no stable 1.4.6 release for borgbackup yet but at least for Fedora (all) + EPEL 10 it should be easy to apply.

For EL9 we use borgbackup 1.2.9 which requires msgpack == 1.1.1. EL8 bundles msgpack so I'll take care of that myself.
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