CVE-2026-2708
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
Description libsoup: libsoup: HTTP Request Smuggling via Duplicate Content-Length Headers Red Hat statement The practical impact is limited because SoupServer is a testing and development utility, not designed for production internet infrastructure. Exploitation requires a deployment topology where SoupServer is serving real traffic behind (or in front of) another HTTP server acting as a proxy —…
Description
libsoup: libsoup: HTTP Request Smuggling via Duplicate Content-Length Headers
Red Hat statement
The practical impact is limited because SoupServer is a testing and development utility, not designed for production internet infrastructure. Exploitation requires a deployment topology where SoupServer is serving real traffic behind (or in front of) another HTTP server acting as a proxy — a scenario that contradicts its intended use.
CVSS v3: 3.7 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N)
Package state
| Product | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 10 | libsoup3 | Fix deferred |
| Red Hat Enterprise Linux 6 | libsoup | Fix deferred |
| Red Hat Enterprise Linux 7 | libsoup | Fix deferred |
| Red Hat Enterprise Linux 8 | libsoup | Fix deferred |
| Red Hat Enterprise Linux 9 | libsoup | Fix deferred |
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | forky | affected | |
| debian | sid | affected | |
| debian | bookworm | affected | |
| debian | bullseye | affected | |
| debian | trixie | affected | |
| sles | affected | | |
| rhel | 6.0 | affected | |
| rhel | 7.0 | affected | |
| rhel | 8.0 | affected | |
| rhel | 9.0 | affected | |
| rhel | 10.0 | affected | |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| gnome | libsoup | - | |
References
- https://access.redhat.com/security/cve/CVE-2026-2708
- https://bugzilla.redhat.com/show_bug.cgi?id=2440743
- https://gitlab.gnome.org/GNOME/libsoup/-/issues/500
- https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/513
- https://security-tracker.debian.org/tracker/CVE-2026-2708
- https://www.suse.com/security/cve/CVE-2026-2708.html
CWEs
CWE-444
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.