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CVE PROGRAM SOURCE RECORD5.9 Medium

CVE-2026-85534

Libsoup: libsoup: http/2 client crash in on_data_source_read_callback when settings initial_window_size shrinks during deferred body read

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Red Hat Red Hat Enterprise Linux 10

Default version status: affected

Red Hat Red Hat Enterprise Linux 6

Default version status: unaffected

Red Hat Red Hat Enterprise Linux 7

Default version status: unaffected

Red Hat Red Hat Enterprise Linux 8

Default version status: unaffected

Red Hat Red Hat Enterprise Linux 9

Default version status: unaffected

References