CVE-2026-85534
Libsoup: libsoup: http/2 client crash in on_data_source_read_callback when settings initial_window_size shrinks during deferred body read
- State
- Published
- Severity
- 5.9 Medium
- Published
- Sep 4, 2026
- Updated
- Sep 4, 2026
- Reserved
- Sep 4, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat |
Weaknesses
- CWE-617 Reachable Assertion
Affected Products
| Product | Versions |
|---|---|
Red Hat Enterprise Linux 10Red Hat | |
Red Hat Enterprise Linux 6Red Hat | |
Red Hat Enterprise Linux 7Red Hat | |
Red Hat Enterprise Linux 8Red Hat | |
Red Hat Enterprise Linux 9Red Hat |
References
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