Reachable Assertion Affecting libsoup3 package, versions <3.0.7-0ubuntu1+esm9


Severity

Recommended
0.0
medium
0
10

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.32% (22nd percentile)

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  • Snyk IDSNYK-UBUNTU2204-LIBSOUP3-19638430
  • published1 Oct 2026
  • disclosed4 Sept 2026

Introduced: 4 Sep 2026

CVE-2026-85534  (opens in a new tab)
CWE-617  (opens in a new tab)

How to fix?

Upgrade Ubuntu:22.04 libsoup3 to version 3.0.7-0ubuntu1+esm9 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libsoup3 package and not the libsoup3 package as distributed by Ubuntu. See How to fix? for Ubuntu:22.04 relevant fixed versions and status.

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 Base Scores

version 3.1