Bug 2543264 - CVE-2026-102556 libsoup: libsoup: Heap buffer overflow from WebSocket Pong signal type confusion [fedora-all]
Summary: CVE-2026-102556 libsoup: libsoup: Heap buffer overflow from WebSocket Pong si...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: libsoup
Version: rawhide
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: ---
Assignee: Gwyn Ciesla
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["8526e307-d6fa-4781-9d20-9...
Depends On:
Blocks: CVE-2026-102556
TreeView+ depends on / blocked
 
Reported: 2026-09-29 15:56 UTC by Srikanth Balasubramanian
Modified: 2026-09-29 15:56 UTC (History)
5 users (show)

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

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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
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