Libsoup: libsoup: denial of service via use-after-free in http/2 server
Summary
| CVE | CVE-2026-4271 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-17 12:16:13 UTC |
| Updated | 2026-05-11 23:20:22 UTC |
| 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). |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.007440000 probability, percentile 0.731220000 (date 2026-05-11)
Problem Types: CWE-416 | CWE-416 Use After Free
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | [email protected] | Secondary | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| 3.1 | CNA | CVSS | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Gnome | Libsoup | - | All | All | All |
| Operating System | Redhat | Enterprise Linux | 10.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 6.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 7.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 8.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 9.0 | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | unaffected 0:3.6.5-3.el10_1.11 * rpm | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/security/cve/CVE-2026-4271 | [email protected] | access.redhat.com | Vendor Advisory |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | Issue Tracking, Vendor Advisory |
| gitlab.gnome.org/GNOME/libsoup/-/issues/496 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | gitlab.gnome.org | Exploit, Issue Tracking, Vendor Advisory |
| access.redhat.com/errata/RHSA-2026:15968 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank fouzhe for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-03-16T14:41:21.942Z | Reported to Red Hat. |
| CNA | 2026-03-16T00:00:00.000Z | Made public. |
Workarounds
CNA: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
There are currently no legacy QID mappings associated with this CVE.