CVE-2026-85534
mediumA flaw was found in libsoup.
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
5.9
5.9 (CVSS v3.1)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Severity source: NVD CVSS v3.1 (secalert@redhat.com)
Timeline (UTC)
Published: 2026-09-04 11:17
Modified: 2026-09-08 19:08
NVD status: Awaiting Analysis
Last synced 1 day ago
Verified against the source API 2026-10-27 06:50 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://access.redhat.com/security/cve/CVE-2026-85534 secalert@redhat.com
- https://bugzilla.redhat.com/show_bug.cgi?id=2528440 secalert@redhat.com
- https://gitlab.gnome.org/GNOME/libsoup/-/blob/master/libsoup/http2/soup-client-message-io-... secalert@redhat.com
- https://gitlab.gnome.org/GNOME/libsoup/-/work_items/551 secalert@redhat.com
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:50 UTC · record ↗