CVE-2026-85534: Reachable Assertion in Red Hat Red Hat Enterprise Linux 10
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.
CVE-2026-85534: Reachable Assertion in Red Hat Red Hat Enterprise Linux 10
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 v3.1
Score 5.9medium
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-09-04T08:57:22.995Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-85534","vendor":"Red Hat"}]
Threat ID: 6a9a9bf4acd9273b496ca317
Added to database: 09/04/2026, 10:22:44 UTC
Last updated: 09/04/2026, 11:22:24 UTC
Views: 5
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