Bug 2543282

Summary:	CVE-2026-102559 libsoup3: libsoup: Heap buffer overflow during WebSocket client-frame masking [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Srikanth Balasubramanian <sbalasub>
Component:	libsoup3	Assignee:	Adrian Vovk <avovk>
Status:	CLOSED ERRATA	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	44	CC:	avovk, gnome-sig, gwync, mcrha
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["5c112865-4fb6-4790-9d61-b8c5d02bc070"]}
Fixed In Version:	libsoup3-3.6.6-11.fc44	Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-11-03 01:38:23 UTC	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:	2543231

Description Srikanth Balasubramanian 2026-09-29 16:36:53 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.

A heap buffer overflow was found in libsoup's client-side WebSocket frame construction / masking path.

Outgoing frames are built in a GByteArray. For a send payload larger than the array can represent (at/above ~2^31), g_byte_array_sized_new() / append truncated the length while xor_with_mask() still iterated the full attacker-/caller-controlled length, writing past the small allocation during masking.

Fixed by rejecting outgoing payloads above MAX_OUTGOING_PAYLOAD_SIZE both before and after extensions process the payload (commit d7f074f8, libsoup 3.7.3).

References:
https://gitlab.gnome.org/GNOME/libsoup/-/work_items/554 (Bug 7)
https://gitlab.gnome.org/GNOME/libsoup/-/commit/d7f074f8

Comment 1 Adrian Vovk 2026-10-27 00:53:58 UTC

rawhide and f45 will be fixed by upgrading to 3.8 w/ mclazy

f44 and f43 will need a backport of the commit

Comment 2 Adrian Vovk 2026-10-27 03:25:46 UTC

*** Bug 2543248 has been marked as a duplicate of this bug. ***

Comment 3 Fedora Update System 2026-10-27 05:13:11 UTC

FEDORA-2026-6c3a4775a6 (libsoup3-3.6.6-6.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-6c3a4775a6

Comment 4 Fedora Update System 2026-10-27 05:13:42 UTC

FEDORA-2026-f06a7887af (libsoup3-3.6.6-11.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-f06a7887af

Comment 5 Fedora Update System 2026-10-28 03:18:13 UTC

FEDORA-2026-6c3a4775a6 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-2026-6c3a4775a6`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-6c3a4775a6

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

Comment 6 Fedora Update System 2026-10-28 04:01:21 UTC

FEDORA-2026-f06a7887af 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-f06a7887af`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-f06a7887af

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

Comment 7 Fedora Update System 2026-11-03 01:38:23 UTC

FEDORA-2026-f06a7887af (libsoup3-3.6.6-11.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.