CVE-2026-6324: Libsoup: libsoup: http request smuggling via unsigned to signed conversion error

Severity: medium (CVSS 4.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-29 · updated 2026-07-21
Weakness: CWE-444

Description

A flaw was found in libsoup. A remote attacker could exploit an unsigned to signed conversion error in the `soup_body_input_stream_read_chunked()` function by sending a malicious HTTP request. This vulnerability occurs when libsoup operates behind a non-libsoup proxy server or as a proxy in front of a non-libsoup backend server. Successful exploitation can allow an attacker to bypass security controls, poison web caches, or gain unauthorized access.

References

https://access.redhat.com/security/cve/CVE-2026-6324
https://bugzilla.redhat.com/show_bug.cgi?id=2458479
https://gitlab.gnome.org/GNOME/libsoup/-/issues/508
https://gitlab.gnome.org/GNOME/libsoup/-/work_items/508

Get alerted when CVE-2026-6324 or the next vulnerability affects your stack