CVE-2026-42010
Gnutls: gnutls: authentication bypass via nul character in username
No known exploitation. EPSS puts it in the 59th percentile. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
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.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.9% chance of exploitation activity in the next 30 days, which ranks it in the 59th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
55 events over 134 days, from the signal feeds we watch.
- Patch availablerecord updated
- Patch availablerecord updated
- Patch availablerecord updated
- Patch availablerecord updated
- Patch availablerecord updated
- Patch availablerecord updated
Affected products
- Red Hat Enterprise Linux 10Operating Systems / linux-distro
- Red Hat Enterprise Linux 10.0 Extended Update SupportOperating Systems / linux-distro
- Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportOperating Systems / linux-distro
- Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-OnOperating Systems / linux-distro
- Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportOperating Systems / linux-distro
- Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-OnOperating Systems / linux-distro
- Red Hat Enterprise Linux 8.8 Telecommunications Update ServiceOperating Systems / linux-distro
- Red Hat Enterprise Linux 8.8 Update Services for SAP SolutionsOperating Systems / linux-distro
And 26 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Scored 7.1 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required LowRequires basic user-level privileges
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity LowData modification is possible but limited in scope or consequence
- Availability NoneNo availability impact
Weaknesses
Sources
References in the record
- access.redhat.com/errata/RHSA-2026:13274
- access.redhat.com/errata/RHSA-2026:20611
- access.redhat.com/errata/RHSA-2026:20612
And 28 more references. See all after sign-in
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