CVE-2026-42010

HIGH
Published May 7, 2026 Modified May 14, 2026 CWE-626

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.

Is your site exposed to CVE-2026-42010?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.1
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

EPSS — Exploit Prediction

0.0013
Probability of exploitation
0.31%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-626 CWE-626

Affected Products

Vendor Product
gnu gnutls
redhat hardened_images
redhat openshift_container_platform
redhat enterprise_linux
redhat enterprise_linux
redhat enterprise_linux
redhat enterprise_linux
redhat enterprise_linux

References

Frequently Asked Questions

What is CVE-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 authentication bypass. This vulnerability allows an attacker to gain unauthorized access by circumventing the authentication process. It has a CVSS v3.1 base score of 7.1 (HIGH).
How severe is CVE-2026-42010? +
CVE-2026-42010 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0013, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-42010? +
CVE-2026-42010 affects products from gnu, redhat, specifically: enterprise_linux, gnutls, hardened_images, openshift_container_platform. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-42010? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-62380

Netty (io.netty:netty-codec-socks) versions 4.2.0.Final through 4.2.16.Final and 4.1.x through 4.1.136.Final contain null byte, CRLF, and credential injection vulnerabilities in the …
CVE-2026-42579 7.5

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's DNS codec does not enforce RFC …
CVE-2026-42040 3.7

Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, the encode() function …
CVE-2026-76816 3.5

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client identifiers, …
CVE-2026-5450 9.8

Calling the scanf family of functions with a %mc (malloc'd character match) in the GNU C Library version 2.7 to …
CVE-2024-39331 9.8

In Emacs before 29.4, org-link-expand-abbrev in lisp/ol.el expands a %(...) link abbrev even when it specifies an unsafe function, such …

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2026-42010 — free, no signup required.