Libsoup: libsoup: http/2 client crash in on_data_source_read_callback when settings initial_window_size shrinks during deferred body read
CVE-2026-85534 is fixed in 10 products on 1 platform, first by gir1.2-soup-3.0 3.0.7-0ubuntu1+esm9, released September 4, 2026. It is not reported as exploited. Patch Radar priority: Routine.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| gir1.2-soup-3.0 · Ubuntu 22.04.1 LTS (jammy) | 3.0.7-0ubuntu1+esm9 | gir1.2-soup-3.0 3.0.7-0ubuntu1+esm9 | Sep 4, 2026 |
| gir1.2-soup-3.0 · Ubuntu 24.04.5 LTS (noble) | 3.4.4-5ubuntu0.9 | gir1.2-soup-3.0 3.4.4-5ubuntu0.9 | Sep 4, 2026 |
| gir1.2-soup-3.0 · Ubuntu 26.04.1 LTS (resolute) | 3.6.6-1ubuntu0.1 | gir1.2-soup-3.0 3.6.6-1ubuntu0.1 | Sep 4, 2026 |
| libsoup · opensuse-leap 16.0 | 3.6.6-160000.4.1 | OPENSUSE-SU-2026:21901-1 | Sep 21, 2026 |
| libsoup · sles 15.6 | 3.4.4-150600.3.53.1 | SUSE-SU-2026:4273-1 | Sep 21, 2026 |
| libsoup · sles 15.7 | 3.4.4-150600.3.53.1 | SUSE-SU-2026:4273-1 | Sep 21, 2026 |
| libsoup · sles 16.0 | 3.6.6-160000.4.1 | SUSE-SU-2026:23866-1 | Sep 21, 2026 |
| libsoup-3.0-0 · Ubuntu 22.04.1 LTS (jammy) | 3.0.7-0ubuntu1+esm9 | libsoup-3.0-0 3.0.7-0ubuntu1+esm9 | Sep 4, 2026 |
| libsoup-3.0-0 · Ubuntu 24.04.5 LTS (noble) | 3.4.4-5ubuntu0.9 | libsoup-3.0-0 3.4.4-5ubuntu0.9 | Sep 4, 2026 |
| libsoup-3.0-0 · Ubuntu 26.04.1 LTS (resolute) | 3.6.6-1ubuntu0.1 | libsoup-3.0-0 3.6.6-1ubuntu0.1 | Sep 4, 2026 |
| libsoup-3.0-common · Ubuntu 22.04.1 LTS (jammy) | 3.0.7-0ubuntu1+esm9 | libsoup-3.0-common 3.0.7-0ubuntu1+esm9 | Sep 4, 2026 |
| libsoup-3.0-common · Ubuntu 24.04.5 LTS (noble) | 3.4.4-5ubuntu0.9 | libsoup-3.0-common 3.4.4-5ubuntu0.9 | Sep 4, 2026 |
| libsoup-3.0-common · Ubuntu 26.04.1 LTS (resolute) | 3.6.6-1ubuntu0.1 | libsoup-3.0-common 3.6.6-1ubuntu0.1 | Sep 4, 2026 |
| libsoup-3.0-tests · Ubuntu 22.04.1 LTS (jammy) | 3.0.7-0ubuntu1+esm9 | libsoup-3.0-tests 3.0.7-0ubuntu1+esm9 | Sep 4, 2026 |
| libsoup-3.0-tests · Ubuntu 24.04.5 LTS (noble) | 3.4.4-5ubuntu0.9 | libsoup-3.0-tests 3.4.4-5ubuntu0.9 | Sep 4, 2026 |
| libsoup-3.0-tests · Ubuntu 26.04.1 LTS (resolute) | 3.6.6-1ubuntu0.1 | libsoup-3.0-tests 3.6.6-1ubuntu0.1 | Sep 4, 2026 |
| libsoup3 · amzn 2023 | 3.7.2-1.amzn2023 | ALAS2023-2026-3144 | Sep 28, 2026 |
| libsoup3-debuginfo · amzn 2023 | 3.7.2-1.amzn2023 | ALAS2023-2026-3144 | Sep 28, 2026 |
| libsoup3-debugsource · amzn 2023 | 3.7.2-1.amzn2023 | ALAS2023-2026-3144 | Sep 28, 2026 |
| libsoup3-devel · amzn 2023 | 3.7.2-1.amzn2023 | ALAS2023-2026-3144 | Sep 28, 2026 |
| libsoup3-doc · amzn 2023 | 3.7.2-1.amzn2023 | ALAS2023-2026-3144 | Sep 28, 2026 |
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