CVE-2026-42010
Gnutls: gnutls: authentication bypass via nul character in username
Published May 7, 2026 · updated Oct 14, 2026 · gnu gnutls
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.
Timeline
Detection, updates, and resolution for this record.
May 7, 2026 · Catalog
Detected
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
Oct 14, 2026 · Catalog
Updated
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
Oct 14, 2026 · NIST NVD
Updated
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
Affected
- cpe gnu/gnutlsversion unspecified
- cpe redhat/enterprise linux10.0
- cpe redhat/enterprise linux6.0
- cpe redhat/enterprise linux7.0
- cpe redhat/enterprise linux8.0
- cpe redhat/enterprise linux9.0
- cpe redhat/hardened imagesversion unspecified
- cpe redhat/openshift container platform4.0
- vendor Red Hat Red Hat Enterprise Linux 10version unspecified
- vendor Red Hat Red Hat Enterprise Linux 10.0 Extended Update Supportversion unspecified
- vendor Red Hat Red Hat Enterprise Linux 8version unspecified
- vendor Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supportversion unspecified
- vendor Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-Onversion unspecified
Sources
- CIRCL Vulnerability LookupCVE-2026-42010
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 authe
vulnerability.circl.lu - CVE.orgCVE-2026-42010
Official CVE identifier
cve.org - FIRST EPSSCVE-2026-42010
30-day exploitation probability 0.9%
first.org - NIST NVDCVE-2026-42010
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 authe
nvd.nist.gov