CVE-2026-42010
Publication date 7 May 2026
Last updated 29 June 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| gnutls28 | 26.04 LTS resolute |
Fixed 3.8.12-2ubuntu1.1
|
| 25.10 questing |
Fixed 3.8.9-3ubuntu2.2
|
|
| 24.04 LTS noble |
Fixed 3.8.3-1.1ubuntu3.6
|
|
| 22.04 LTS jammy |
Fixed 3.7.3-4ubuntu1.9
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Not affected
|
Notes
mrmajumder
xenial and bionic are not-affected: binary PSK identity support (the username_len field and the length parameter of _gnutls_psk_pwd_find_entry) was introduced in 3.6.13.
Severity score breakdown
CVSS version: CVSS v3.0
Base score
7.1 · High
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
References
Related Ubuntu Security Notices (USN)
- USN-8284-1
- GnuTLS vulnerabilities
- 20 May 2026