Bug#1140924: libsoup3: CVE-2026-12549

[Salvatore Bonaccorso]

Source: libsoup3
Version: 3.6.6-1
Severity: important
Tags: security upstream
Forwarded: https://gitlab.gnome.org/GNOME/libsoup/-/work_items/516
X-Debbugs-Cc: carnil at debian.org, Debian Security Team <team at security.debian.org>

Hi,

The following vulnerability was published for libsoup3.

CVE-2026-12549[0]:
| The fix for CVE-2026-2443 was regressed by a subsequent rework
| commit that replaced specific overflow checks with a general signed
| comparison. When a client sends a Range request with a suffix length
| exceeding the content size, the resulting negative start value is
| not properly clamped, leading to malformed HTTP 206 responses and
| log flooding.


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-12549
    https://www.cve.org/CVERecord?id=CVE-2026-12549
[1] https://gitlab.gnome.org/GNOME/libsoup/-/work_items/516

Please adjust the affected versions in the BTS as needed.

Regards,
Salvatore