CVE-2026-85534

NameCVE-2026-85534
DescriptionA 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libsoup2.4 (PTS)bookworm2.74.3-1+deb12u1vulnerable
trixie2.74.3-10.1vulnerable
libsoup3 (PTS)bookworm3.2.3-0+deb12u2vulnerable
trixie3.6.5-3vulnerable
forky, sid3.6.6-1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libsoup2.4source(unstable)(unfixed)
libsoup3source(unstable)(unfixed)

Notes

https://gitlab.gnome.org/GNOME/libsoup/-/work_items/551
https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/561

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