dbcve.org
Hardened ImagesApplication · Redhat

CVE-2026-42010

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vulnerability in GnuTLS allows RSA-PSK authentication to incorrectly match usernames containing NUL characters with truncated versions of the same username, enabling authentication bypass through specially crafted usernames.

MitigationUpdate GnuTLS to the latest version containing the security fix and verify that RSA-PSK username validation properly handles NUL bytes.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Hardened ImagesApplication
Affected:all versions
Openshift Container PlatformApplication
Affected:= 4.0
Enterprise LinuxOperating system
Affected:= 6.0= 7.0= 8.0= 9.0= 10.0
GnutlsApplication
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify GnuTLS installation and version
    Run 'gnutls-cli --version' or 'gnutls-serv --version' to determine the installed GnuTLS version. On RHEL systems, also check 'rpm -q gnutls' or 'rpm -qa | grep gnutls'. Compare your installed version to the affected range (all versions are affected).
    Affected if GnuTLS is installed and no security patch has been applied.
  2. Confirm RSA-PSK key exchange is in use
    Review server or application configuration files for authentication settings. Look for configurations that enable RSA-PSK (Pre-Shared Key with RSA key exchange) such as 'tls-psk' or 'rsa-psk' cipher suites or authentication methods. Check application-specific configs that use GnuTLS for TLS termination or authentication.
    Affected if RSA-PSK authentication methods are enabled in the GnuTLS-using server or application.
  3. Verify username validation mechanisms
    Examine the application or service logs that handle GnuTLS authentication. Check if the application performs input validation on usernames before authentication. Look for how usernames are processed in the authentication code path.
    Affected if The server does not explicitly reject usernames containing NUL characters before performing RSA-PSK authentication.
  4. Audit authentication logs for anomalous attempts
    Review authentication logs for any failed or successful login attempts with unusual username patterns. Search for patterns where usernames might have been truncated or where NUL-like characters could be present.
    Affected if Logs show authentication successes using usernames that differ only by hidden characters.

You are affected if your environment uses GnuTLS with RSA-PSK authentication enabled and does not filter out NUL characters in usernames.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update GnuTLS to the latest version containing the security fix and verify that RSA-PSK username validation properly handles NUL bytes.

Fix this in Hardened Images Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-42010 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-42010 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data