CVE-2026-85534
A flaw was found in libsoup. When a client sends an HTTP/2 request body from a non-pollable input stream, the library can buffer more data than the current flow-control window later allows. A malicious HTTP/2 server can shrink SETTINGS_INITIAL_WINDOW_SIZE while that buffered read is still in progress. The client then copies the full buffer into a smaller DATA callback without a runtime bounds check, which can abort the process or fail the HTTP/2 session.
- Score
- CVSS 3.1 5.9 Medium
- Status
- Awaiting Analysis - secalert@redhat.com
- Published
- 2026-09-04
- Last modified
- 2026-09-04
- Weaknesses
- CWE-617
Affected products
References
- https://access.redhat.com/security/cve/CVE-2026-85534
- https://bugzilla.redhat.com/show_bug.cgi?id=2528440
- https://gitlab.gnome.org/GNOME/libsoup/-/blob/master/libsoup/http2/soup-client-message-io-http2.c
- https://gitlab.gnome.org/GNOME/libsoup/-/work_items/551
