Bug 2543264

Summary:	CVE-2026-102556 libsoup: libsoup: Heap buffer overflow from WebSocket Pong signal type confusion [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Srikanth Balasubramanian <sbalasub>
Component:	libsoup	Assignee:	Gwyn Ciesla <gwync>
Status:	NEW ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	rawhide	CC:	gwync, mclasen, rhughes, rstrode, tpopela
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["8526e307-d6fa-4781-9d20-950af5baeefc"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2543229

Description Srikanth Balasubramanian 2026-09-29 15:56:47 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 type-confusion heap overflow was found in libsoup's WebSocket Pong handling.

SoupWebsocketConnection::pong is declared to deliver a GBytes payload, but receive_pong() emitted a GByteArray pointer via g_signal_emit() and then unreffed the GByteArray. Handlers that treated the argument as GBytes (as documented) operated on the wrong object layout, resulting in heap memory corruption / overflow conditions under ASan.

Fixed upstream by converting the buffer with g_byte_array_free_to_bytes() before emission (commit d2cbaf25, libsoup 3.7.3).

References:
https://gitlab.gnome.org/GNOME/libsoup/-/work_items/554 (Bug 2)
https://gitlab.gnome.org/GNOME/libsoup/-/commit/d2cbaf25