Medium severity · published Mar 17, 2026
CVE-2026-3632
Libsoup: libsoup: http smuggling and server-side request forgery via malformed hostnames
5.5
CVSS
0.2%
EPSS
No
On KEV
Description
A flaw was found in libsoup, a library used by applications to send network requests. This vulnerability occurs because libsoup does not properly validate hostnames, allowing special characters to be injected into HTTP headers. A remote attacker could exploit this to perform HTTP smuggling, where they can send hidden, malicious requests alongside legitimate ones. In certain situations, this could lead to Server-Side Request Forgery (SSRF), enabling an attacker to force the server to make unauthorized requests to other internal or external systems. The impact is low, as SoupServer is not actually used in internet infrastructure.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 6 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 7 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 9 · Red Hat
All versions, or not specified · source: vendor
EL
Enterprise Linux · Redhat
6.0; 7.0; 8.0; 9.0; 10.0 · source: NVD
LI
Libsoup · Gnome
All versions, or not specified · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3632
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-3632
Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-3632
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2445127
Exploit
https://gitlab.gnome.org/GNOME/libsoup/-/issues/483
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