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Vulnerability · Published May 7, 2026 · Assigned by redhat

CVE-2026-42010Gnutls: gnutls: authentication bypass via nul character in username

High 7.1

In plain English

A high-severity security flaw in gnutls. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 64% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.1High
Exploit odds (30 days)1.1%top 35.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

A flaw was found in gnutls. Servers configured with RSA-PSK (Rivest–Shamir–Adleman – Pre-Shared Key) wrongfully matched usernames containing a NUL character with truncated usernames. A remote attacker could exploit this by sending a specially crafted username, leading to an authentication bypass. This vulnerability allows an attacker to gain unauthorized access by circumventing the authentication process.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10gnutls3.8.10-4.el10_2ALSA-2026:20613
AlmaLinux:8gnutls3.6.16-8.el8_10.6ALSA-2026:20611
AlmaLinux:9gnutls3.8.10-4.el9_8ALSA-2026:20612
AlmaLinux:10gnutls-c++3.8.10-4.el10_2ALSA-2026:20613
AlmaLinux:8gnutls-c++3.6.16-8.el8_10.6ALSA-2026:20611
AlmaLinux:9gnutls-c++3.8.10-4.el9_8ALSA-2026:20612
AlmaLinux:10gnutls-dane3.8.10-4.el10_2ALSA-2026:20613
AlmaLinux:8gnutls-dane3.6.16-8.el8_10.6ALSA-2026:20611
AlmaLinux:9gnutls-dane3.8.10-4.el9_8ALSA-2026:20612
AlmaLinux:10gnutls-devel3.8.10-4.el10_2ALSA-2026:20613
AlmaLinux:8gnutls-devel3.6.16-8.el8_10.6ALSA-2026:20611
AlmaLinux:9gnutls-devel3.8.10-4.el9_8ALSA-2026:20612
AlmaLinux:10gnutls-fips3.8.10-4.el10_2ALSA-2026:20613
AlmaLinux:10gnutls-utils3.8.10-4.el10_2ALSA-2026:20613
AlmaLinux:8gnutls-utils3.6.16-8.el8_10.6ALSA-2026:20611
AlmaLinux:9gnutls-utils3.8.10-4.el9_8ALSA-2026:20612
Alpine:v3.20gnutls3.8.13-r0ALPINE-CVE-2026-42010
Alpine:v3.21gnutls3.8.13-r0ALPINE-CVE-2026-42010
Alpine:v3.22gnutls3.8.13-r0ALPINE-CVE-2026-42010
Alpine:v3.23gnutls3.8.13-r0ALPINE-CVE-2026-42010
Alpine:v3.24gnutls3.8.13-r0ALPINE-CVE-2026-42010
Debian:12gnutls283.7.9-2+deb12u7DEBIAN-CVE-2026-42010
Debian:13gnutls283.8.9-3+deb13u4DEBIAN-CVE-2026-42010
Debian:14gnutls283.8.13-1DEBIAN-CVE-2026-42010
Rocky Linux:10gnutls0:3.8.10-4.el10_2RLSA-2026:20613
Rocky Linux:8gnutls0:3.6.16-8.el8_10.6RLSA-2026:20611
Rocky Linux:9gnutls0:3.8.10-4.el9_8RLSA-2026:20612
Ubuntu:22.04:LTSgnutls283.7.3-4ubuntu1.9UBUNTU-CVE-2026-42010
Ubuntu:24.04:LTSgnutls283.8.3-1.1ubuntu3.6UBUNTU-CVE-2026-42010
Ubuntu:25.10gnutls283.8.9-3ubuntu2.2UBUNTU-CVE-2026-42010
Ubuntu:26.04:LTSgnutls283.8.12-2ubuntu1.1UBUNTU-CVE-2026-42010

Affected products (as reported)

VendorProductVersions
gnutls 3.6.13 – before 3.8.13
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support see references
Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support see references
Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On see references
Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On see references
Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support see references
Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support see references
Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On see references
Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On see references
Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service see references
Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service see references
Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions see references
Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions see references
Red Hat Red Hat Enterprise Linux 9 see references
Red Hat Red Hat Enterprise Linux 9 see references
Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions see references
Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions see references
Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support see references
Red Hat Red Hat OpenShift Container Platform 4.12 see references
Red Hat Red Hat OpenShift Container Platform 4.13 see references
Red Hat Red Hat OpenShift Container Platform 4.14 see references
Red Hat Red Hat OpenShift Container Platform 4.15 see references
Red Hat Red Hat OpenShift Container Platform 4.16 see references
Red Hat Red Hat OpenShift Container Platform 4.17 see references
Red Hat Red Hat OpenShift Container Platform 4.18 see references
Red Hat Red Hat OpenShift Container Platform 4.19 see references

Weakness: CWE-170, CWE-626 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

References