Description
A request smuggling vulnerability exists in libsoup's HTTP/1 header parsing logic. The soup_message_headers_append_common() function in libsoup/soup-message-headers.c unconditionally appends each header value without validating for duplicate or conflicting Content-Length fields. This allows an attacker to send HTTP requests containing multiple Content-Length headers with differing values.
Affected products
gnome: libsoup; redhat: enterprise linux
References4
- access.redhat.com/security/cve/CVE-2026-2708 Vendor Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2440743 Issue TrackingVendor Advisory
- gitlab.gnome.org/GNOME/libsoup/-/issues/500 ExploitIssue TrackingVendor Advisory
- gitlab.gnome.org/GNOME/libsoup/-/merge_requests/513 Issue Tracking
Metrics
- CVSS 3.1
-
5.3
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - EPSS — exploit probability
- 0% percentile: 25 · as of 13 November 2026
- CWE
- CWE-444
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.