Vulnerability in GNOME Libsoup
CVE-2026-3633
A flaw was found in libsoup. A remote attacker, by controlling the method parameter of the `soup_message_new()` function, could inject arbitrary headers and additional request data. This vulnerability, known as CRLF (Carriage Return Line Feed) injection, occurs because the method value is not properly escaped during request line construction, potentially leading to HTTP request injection.
Vulnerability class: CRLF Injection
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.9 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.004 (28.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.001
Affected products
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-3633 (vdb-entry, Vendor Advisory)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking, Issue Tracking, Vendor Advisory)
- gitlab.gnome.org/GNOME/libsoup/-/issues/484 (Exploit, Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-3633?
- CVE-2026-3633 is a low-severity vulnerability in GNOME Libsoup, classified under CRLF Injection. CVSS score: 3.9/10. Published 2026-03-17.
- How severe is CVE-2026-3633?
- Low severity. CVSS v3 base score is 3.9 out of 10.