Bug 2543279 - CVE-2026-102558 libsoup3: libsoup: Heap buffer overflow during WebSocket receive-buffer growth [fedora-all]
Summary: CVE-2026-102558 libsoup3: libsoup: Heap buffer overflow during WebSocket rece...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: libsoup3
Version: rawhide
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: ---
Assignee: Gwyn Ciesla
QA Contact:
URL:
Whiteboard: {"flaws": ["b941a0b0-e1e1-45da-a415-8...
Depends On:
Blocks: CVE-2026-102558
TreeView+ depends on / blocked
 
Reported: 2026-09-29 16:23 UTC by Srikanth Balasubramanian
Modified: 2026-09-29 16:23 UTC (History)
3 users (show)

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


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Description Srikanth Balasubramanian 2026-09-29 16:23:41 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 WebSocket incoming receive buffer handling.

Incoming frames are accumulated in a GByteArray. With max-incoming-payload-size set to 0 (unlimited), a peer could declare a multi-GiB payload and stream it until the buffer length wrapped in g_byte_array_set_size() while the read still targeted the original offset, writing past the allocation.

Fixed by rejecting payload lengths above what the receive buffer can represent as soon as the frame header is parsed, before buffering the payload (commit 381a474f, libsoup 3.7.3). Such frames are closed as SOUP_WEBSOCKET_CLOSE_TOO_BIG.

References:
https://gitlab.gnome.org/GNOME/libsoup/-/work_items/554 (Bug 6)
https://gitlab.gnome.org/GNOME/libsoup/-/commit/381a474f


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