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CVE Record

CVE-2026-42010: Gnutls: gnutls: authentication bypass via nul character in username

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.

HighCVSS 7.1Not KEV-listedUpdated
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Potential ATT&CK relevance

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CWE-170: Exact CWE lookup

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CWE-626: Exact CWE lookup

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Credential and access behavior lookup

The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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CVE-2026-42010 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.1 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
7Timeline events
2ADP providers
42Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.1CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N2.84.2redhat
7.1CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N2.84.2redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.1High
CVSS 3.1 vector shape for CVE-2026-42010Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. Source timelineredhat

    Made public.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. Source timelineredhat

    Reported to Red Hat.

  6. CVE publishedCVE Program

    The CVE record was published.

  7. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPgnutls: gnutls: Authentication Bypass via NUL Character in Username
other:Red Hat severity ratingcvssV3_1
  • 2026-05-06T16:57:37.044Z: Reported to Red Hat.
  • 2026-04-29T00:00:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Unknown vendorgnutlsgnutls, 0Listed
Red HatRed Hat Enterprise Linux 10gnutls, 0:3.8.10-4.el10_2affected
Red HatRed Hat Enterprise Linux 10.0 Extended Update Supportgnutls, 0:3.8.9-9.el10_0.19affected
Red HatRed Hat Enterprise Linux 8gnutls, 0:3.6.16-8.el8_10.6affected
Red HatRed Hat Enterprise Linux 8gnutls, 0:3.6.16-8.el8_10.6affected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supportgnutls, 0:3.6.14-10.el8_4.1affected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supportlibtasn1, 0:4.13-3.el8_4.1affected
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-Ongnutls, 0:3.6.14-10.el8_4.1affected
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-Onlibtasn1, 0:4.13-3.el8_4.1affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supportgnutls, 0:3.6.16-5.el8_6.5affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supportlibtasn1, 0:4.13-3.el8_6.2affected
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-Ongnutls, 0:3.6.16-5.el8_6.5affected
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-Onlibtasn1, 0:4.13-3.el8_6.2affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicegnutls, 0:3.6.16-7.el8_8.4affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicelibtasn1, 0:4.13-4.el8_8.1affected
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP Solutionsgnutls, 0:3.6.16-7.el8_8.4affected
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP Solutionslibtasn1, 0:4.13-4.el8_8.1affected
Red HatRed Hat Enterprise Linux 9gnutls, 0:3.8.10-4.el9_8affected
Red HatRed Hat Enterprise Linux 9gnutls, 0:3.8.10-4.el9_8affected
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP Solutionsgnutls, 0:3.7.6-21.el9_2.7affected
Red HatRed Hat Enterprise Linux 9.4 Update Services for SAP Solutionsgnutls, 0:3.8.3-4.el9_4.6affected
Red HatRed Hat Enterprise Linux 9.6 Extended Update Supportgnutls, 0:3.8.3-6.el9_6.4affected
Red HatRed Hat OpenShift Container Platform 4.12openshift/ose-rhel-coreos-8, 412.86.202608241157-0affected
Red HatRed Hat OpenShift Container Platform 4.13openshift/ose-rhel-coreos-9, 413.92.202609080414-0affected
Red HatRed Hat OpenShift Container Platform 4.14openshift/ose-rhel-coreos-9, 414.92.202609011250-0affected
Red HatRed Hat OpenShift Container Platform 4.15openshift/ose-rhel-coreos-9, 415.92.202609140326-0affected
Red HatRed Hat OpenShift Container Platform 4.16openshift/ose-rhel-coreos-9, 416.94.202608150307-0affected
Red HatRed Hat OpenShift Container Platform 4.17openshift/ose-rhel-coreos-9, 417.94.202608250221-0affected
Red HatRed Hat OpenShift Container Platform 4.18openshift/ose-rhel-coreos-9, 418.94.202608142238-0affected
Red HatRed Hat OpenShift Container Platform 4.19openshift/ose-rhel-coreos-9, 4.19.9.6.202607151909-0affected
Weakness

CWE details

CWE-170CWE-626

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-170 · source CWE mapping

Improper Null Termination

Improper Null Termination represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-626 · source CWE mapping

Null Byte Interaction Error (Poison Null Byte)

Null Byte Interaction Error (Poison Null Byte) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs