{"id":"UBUNTU-CVE-2026-85534","details":"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.","modified":"2026-10-22T04:41:56.614327365Z","published":"2026-09-04T11:17:00Z","related":["USN-8890-1","USN-8890-2"],"upstream":["CVE-2026-85534"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-85534"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-85534"},{"type":"REPORT","url":"https://gitlab.gnome.org/GNOME/libsoup/-/work_items/551"},{"type":"REPORT","url":"https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/561"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8890-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8890-2"}],"affected":[{"package":{"name":"libsoup3","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/libsoup3?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.0.7-0ubuntu1+esm9"}]}],"versions":["3.0.4-2","3.0.4-3","3.0.5-1","3.0.7-0ubuntu1","3.0.7-0ubuntu1+esm1","3.0.7-0ubuntu1+esm2","3.0.7-0ubuntu1+esm3","3.0.7-0ubuntu1+esm4","3.0.7-0ubuntu1+esm5","3.0.7-0ubuntu1+esm6","3.0.7-0ubuntu1+esm7","3.0.7-0ubuntu1+esm8"],"ecosystem_specific":{"binaries":[{"binary_name":"gir1.2-soup-3.0","binary_version":"3.0.7-0ubuntu1+esm9"},{"binary_version":"3.0.7-0ubuntu1+esm9","binary_name":"libsoup-3.0-0"},{"binary_name":"libsoup-3.0-common","binary_version":"3.0.7-0ubuntu1+esm9"},{"binary_version":"3.0.7-0ubuntu1+esm9","binary_name":"libsoup-3.0-tests"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-85534.json"}},{"package":{"name":"libsoup3","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libsoup3?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.4-5ubuntu0.9"}]}],"versions":["3.4.2-4","3.4.4-1","3.4.4-2","3.4.4-4","3.4.4-5","3.4.4-5build1","3.4.4-5build2","3.4.4-5ubuntu0.1","3.4.4-5ubuntu0.2","3.4.4-5ubuntu0.3","3.4.4-5ubuntu0.4","3.4.4-5ubuntu0.5","3.4.4-5ubuntu0.6","3.4.4-5ubuntu0.7","3.4.4-5ubuntu0.8"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"gir1.2-soup-3.0","binary_version":"3.4.4-5ubuntu0.9"},{"binary_name":"libsoup-3.0-0","binary_version":"3.4.4-5ubuntu0.9"},{"binary_version":"3.4.4-5ubuntu0.9","binary_name":"libsoup-3.0-common"},{"binary_name":"libsoup-3.0-tests","binary_version":"3.4.4-5ubuntu0.9"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-85534.json"}},{"package":{"name":"libsoup3","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/libsoup3?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.6.6-1ubuntu3"}]}],"versions":["3.6.6-1"],"ecosystem_specific":{"binaries":[{"binary_name":"gir1.2-soup-3.0","binary_version":"3.6.6-1ubuntu3"},{"binary_name":"libsoup-3.0-0","binary_version":"3.6.6-1ubuntu3"},{"binary_name":"libsoup-3.0-common","binary_version":"3.6.6-1ubuntu3"},{"binary_name":"libsoup-3.0-tests","binary_version":"3.6.6-1ubuntu3"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-85534.json"}},{"package":{"name":"libsoup3","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libsoup3?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.6.6-1ubuntu0.1"}]}],"versions":["3.6.5-4","3.6.5-5","3.6.5-6","3.6.5-7","3.6.5-9","3.6.6-1"],"ecosystem_specific":{"binaries":[{"binary_name":"gir1.2-soup-3.0","binary_version":"3.6.6-1ubuntu0.1"},{"binary_name":"libsoup-3.0-0","binary_version":"3.6.6-1ubuntu0.1"},{"binary_version":"3.6.6-1ubuntu0.1","binary_name":"libsoup-3.0-common"},{"binary_version":"3.6.6-1ubuntu0.1","binary_name":"libsoup-3.0-tests"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-85534.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}