Vulnerability 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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
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-m
- https://gitlab.gnome.org/GNOME/libsoup/-/work_items/551
FAQ
What is CVE-2026-85534?
CVE-2026-85534 is a vulnerability with a CVSS score of 5.9 (MEDIUM). 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 maliciou...
How severe is CVE-2026-85534?
CVE-2026-85534 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-85534?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.