High severity · published Mar 17, 2026
CVE-2026-4271
Libsoup: libsoup: denial of service via use-after-free in http/2 server
7.5
CVSS
0.9%
EPSS
No
On KEV
Description
A flaw was found in libsoup, a library for handling HTTP requests. This vulnerability, known as a Use-After-Free, occurs in the HTTP/2 server implementation. A remote attacker can exploit this by sending specially crafted HTTP/2 requests that cause authentication failures. This can lead to the application attempting to access memory that has already been freed, potentially causing application instability or crashes, resulting in a Denial of Service (DoS).
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 58% 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 10.0 Extended Update Support · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 6 · 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-2026-4271
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-4271
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:15968
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:17482
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:19143
Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-4271
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2448044
Exploit
https://gitlab.gnome.org/GNOME/libsoup/-/issues/496
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