CVE-2026-42010: vLLM — HIGH

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....

Full CISO analysis pending enrichment.

What systems are affected?

Package	Ecosystem	Vulnerable Range	Patched
vLLM	pip	—	No patch
85.4K 129 dependents Pushed yesterday 22% patched ~51d to patch Full package profile →
discovery/discovery-server-rhel9	—	—	No patch
discovery/discovery-ui-rhel9	—	—	No patch
gnutls	—	—	No patch
gnutls-main	—	—	No patch
libtasn1	—	—	No patch
rhaiis/model-opt-cuda-rhel9	—	—	No patch
rhcos	—	—	No patch
rhui5/cds-rhel9	—	—	No patch
rhui5/haproxy-rhel9	—	—	No patch
rhui5/installer-rhel9	—	—	No patch
rhui5/rhua-rhel9	—	—	No patch

How severe is it?

CVSS 3.1

7.1 / 10

EPSS

N/A

Exploitation Status

No known exploitation

Sophistication

N/A

What is the attack surface?

AV Network

AC Low

PR Low

UI None

S Unchanged

C High

I Low

A None

What should I do?

No patch available

Monitor for updates. Consider compensating controls or temporary mitigations.

Which compliance frameworks are affected?

Compliance analysis pending. Sign in for full compliance mapping when available.

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.

Is CVE-2026-42010 actively exploited?

No confirmed active exploitation of CVE-2026-42010 has been reported, but organizations should still patch proactively.

How to fix CVE-2026-42010?

No patch is currently available. Monitor vendor advisories for updates.

What is the CVSS score for CVE-2026-42010?

CVE-2026-42010 has a CVSS v3.1 base score of 7.1 (HIGH).

What are the technical details?

Original Advisory

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.

Weaknesses (CWE)

CWE-170 Improper Null Termination

CWE-170 — Improper Null Termination: The product does not terminate or incorrectly terminates a string or array with a null character or equivalent terminator.

[Requirements] Use a language that is not susceptible to these issues. However, be careful of null byte interaction errors (CWE-626) with lower-level constructs that may be written in a language that is susceptible.
[Implementation] Ensure that all string functions used are understood fully as to how they append null characters. Also, be wary of off-by-one errors when appending nulls to the end of strings.

Source: MITRE CWE corpus.