Improper Authentication in GnuTLS - CVE-2026-42010

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Main Vulnerability Database Vulnerabilities #VU128571

Improper Authentication in GnuTLS - CVE-2026-42010

Published: April 30, 2026


Vulnerability identifier: #VU128571
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-42010
CWE-ID: CWE-287
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to bypass authentication.

The vulnerability exists due to improper authentication in RSA-PSK username matching when processing usernames containing a NUL character. A remote attacker can supply a specially crafted username to bypass authentication.


Affected software

GnuTLS
Debian Linux
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Micro
SUSE Linux Enterprise Micro for Rancher
Anolis OS
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Basesystem Module
openSUSE Leap
Ubuntu
openEuler
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
gnutls28 (Ubuntu package)
gnutls (Red Hat package)
gnutls-devel
gnutls-utils
gnutls-help
gnutls-debugsource
gnutls-debuginfo
gnutls
gnutls-dane
gnutls-c++
libgnutls30-debuginfo
gnutls-guile
libgnutlsxx28
libgnutls-devel
libgnutlsxx-devel
gnutls-guile-debuginfo
libgnutls30
libgnutls-devel-64bit
libgnutls30-hmac-64bit
libgnutls30-64bit-debuginfo
libgnutls30-64bit
libgnutls30-hmac-32bit
libgnutls-devel-32bit
libgnutls30-32bit
libgnutls30-32bit-debuginfo
libgnutlsxx28-debuginfo
libgnutls30-hmac
gnutls28 (Debian package)
gnutls-doc
libgnutlsxx30-debuginfo
libgnutlsxx30
libtasn1 (Red Hat package)
Red Hat OpenShift Container Platform

How to mitigate CVE-2026-42010

Install security update from vendor's website.

GnuTLS - update to 3.8.13
gnutls28 (Ubuntu package) - addressed in versions 3.4.10-4ubuntu1.9+esm3, 3.5.18-1ubuntu1.6+esm3, 3.6.13-2ubuntu1.12+esm2, 3.7.3-4ubuntu1.9, 3.8.3-1.1ubuntu3.6, 3.8.9-3ubuntu2.2, 3.8.12-2ubuntu1.1
gnutls (Red Hat package) - addressed in versions 3.6.14-10.el8_4.1, 3.6.16-5.el8_6.5, 3.7.6-21.el9_2.7, 3.8.9-9.el10_0.19
gnutls-devel - addressed in versions 3.6.14-22, 3.7.2-23, 3.8.2-14
gnutls-utils - addressed in versions 3.6.14-22, 3.7.2-23, 3.8.2-14
gnutls-help - addressed in versions 3.6.14-22, 3.7.2-23, 3.8.2-14
gnutls-debugsource - addressed in versions 3.6.14-22, 3.7.2-23, 3.8.2-14
gnutls-debuginfo - addressed in versions 3.6.14-22, 3.7.2-23, 3.8.2-14
gnutls - addressed in versions 3.6.14-22, 3.7.2-23, 3.8.2-14
gnutls-utils - addressed in versions 3.6.16-8.0.2, 3.8.2-7
gnutls-devel - addressed in versions 3.6.16-8.0.2, 3.8.2-7
gnutls-dane - addressed in versions 3.6.16-8.0.2, 3.8.2-7
gnutls-c++ - addressed in versions 3.6.16-8.0.2, 3.8.2-7
gnutls - addressed in versions 3.6.16-8.0.2, 3.8.2-7
libgnutls30-debuginfo - addressed in versions 3.7.3-150400.4.59.1, 3.7.3-150400.24.2, 3.8.3-150600.4.20.1
gnutls - addressed in versions 3.7.3-150400.4.59.1, 3.7.3-150400.24.2, 3.8.3-150600.4.20.1
gnutls-guile - update to 3.7.3-150400.4.59.1
libgnutlsxx28 - update to 3.7.3-150400.4.59.1
libgnutls-devel - addressed in versions 3.7.3-150400.4.59.1, 3.8.3-150600.4.20.1
libgnutlsxx-devel - addressed in versions 3.7.3-150400.4.59.1, 3.8.3-150600.4.20.1
gnutls-guile-debuginfo - update to 3.7.3-150400.4.59.1
libgnutls30 - addressed in versions 3.7.3-150400.4.59.1, 3.7.3-150400.24.2, 3.8.3-150600.4.20.1
libgnutls-devel-64bit - addressed in versions 3.7.3-150400.4.59.1, 3.8.3-150600.4.20.1
libgnutls30-hmac-64bit - update to 3.7.3-150400.4.59.1
libgnutls30-64bit-debuginfo - addressed in versions 3.7.3-150400.4.59.1, 3.8.3-150600.4.20.1
libgnutls30-64bit - addressed in versions 3.7.3-150400.4.59.1, 3.8.3-150600.4.20.1
libgnutls30-hmac-32bit - update to 3.7.3-150400.4.59.1
libgnutls-devel-32bit - addressed in versions 3.7.3-150400.4.59.1, 3.8.3-150600.4.20.1
libgnutls30-32bit - addressed in versions 3.7.3-150400.4.59.1, 3.8.3-150600.4.20.1
libgnutls30-32bit-debuginfo - addressed in versions 3.7.3-150400.4.59.1, 3.8.3-150600.4.20.1
gnutls-debugsource - addressed in versions 3.7.3-150400.4.59.1, 3.7.3-150400.24.2, 3.8.3-150600.4.20.1
libgnutlsxx28-debuginfo - update to 3.7.3-150400.4.59.1
libgnutls30-hmac - addressed in versions 3.7.3-150400.4.59.1, 3.7.3-150400.24.2
gnutls-debuginfo - addressed in versions 3.7.3-150400.4.59.1, 3.7.3-150400.24.2, 3.8.3-150600.4.20.1
gnutls28 (Debian package) - addressed in versions 3.7.9-2+deb12u7, 3.8.9-3+deb13u4
gnutls-doc - update to 3.8.2-7
gnutls-dane - update to 3.8.2-14
libgnutlsxx30-debuginfo - update to 3.8.3-150600.4.20.1
libgnutlsxx30 - update to 3.8.3-150600.4.20.1
libtasn1 (Red Hat package) - addressed in versions 4.13-3.el8_4.1, 4.13-3.el8_6.2
Red Hat OpenShift Container Platform - addressed in versions 4.20.28, 4.21.23, 4.22.4

External References

Related Security Bulletins