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CVE Record

CVE-2026-42015: Gnutls: gnutls: memory corruption due to off-by-one error in pkcs#12 bag handling

A flaw was found in gnutls. An off-by-one error exists in the PKCS#12 bag element bounds check. This vulnerability allows an remote attacker to write past the internal array of a PKCS#12 bag when appending to a bag that already contains 32 elements. This memory corruption could lead to a denial of service (DoS) or potentially other unspecified impacts.

MediumCVSS 5.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2026-42015 is a memory corruption flaw in GnuTLS PKCS#12 bag handling. A remote attacker could trigger a write just past an internal array when a bag already has 32 elements. The documented impact is denial of service, with other impacts unspecified.

Executive priority

Treat this as a routine but timely infrastructure patching item. It is remotely reachable and unauthenticated, but current public evidence points mainly to service disruption rather than confirmed compromise or active exploitation.

Technical view

The flaw is an off-by-one bounds check error, classified as CWE-193, in PKCS#12 bag element handling. Red Hat rates it medium with CVSS 3.1 score 5.3: network reachable, low complexity, no privileges or user interaction, unchanged scope, and low availability impact.

Likely exposure

Exposure is most relevant on affected Red Hat Enterprise Linux 8, 9, and 10 systems with gnutls or listed libtasn1 packages installed, especially where services process untrusted PKCS#12 data. Systems not using PKCS#12 processing have lower practical exposure.

Exploitation context

The source bundle does not cite active exploitation, and KEV status is false. Public evidence supports a remote denial-of-service risk from memory corruption. The sources do not substantiate reliable code execution or broader impact beyond unspecified possibilities.

Researcher notes

Key uncertainty is exploitability beyond denial of service. The vulnerable condition involves appending to a PKCS#12 bag already containing 32 elements. Validation should focus on package inventory and reachable code paths, not broad assumptions that all TLS use is affected.

Mitigation direction

  • Apply the applicable Red Hat security advisory updates for affected gnutls and libtasn1 packages.
  • Prioritize exposed systems that process certificates, key stores, or PKCS#12 data from untrusted sources.
  • Check Red Hat CVE and RHSA pages for exact fixed package versions for each RHEL stream.
  • If updates are delayed, reduce or disable untrusted PKCS#12 processing where operationally feasible.

Validation and detection

  • Inventory RHEL 8, 9, and 10 systems for affected gnutls and libtasn1 package versions.
  • Map which applications or services invoke GnuTLS PKCS#12 import or bag handling paths.
  • Confirm installed package versions against the relevant Red Hat advisory for that OS stream.
  • Monitor crash, restart, or availability telemetry for services processing certificate bundles.
Prepared
Confidence
high
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-193: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Container behavior lookup

The affected technology mentions containers, so container-specific ATT&CK technique 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 · low confidence lookup

CVE-2026-42015 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.3 (3.1)
Known Exploited
No
Published

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

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.

1CVSS vectors
5Timeline events
1ADP providers
16Source links

SSVC decision data

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

CVSS vector scores

1 official score

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
5.3CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L3.91.4redhat

Vulnerability scoring details

Base CVSS 3.1 score

5.3Medium
CVSS 3.1 vector shape for CVE-2026-42015Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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. Source timelineredhat

    Made public.

  3. Source timelineredhat

    Reported to Red Hat.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

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

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
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 9.4 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 Discovery 2discovery/discovery-server-rhel9, 1782159791affected
Red HatRed Hat Discovery 2discovery/discovery-ui-rhel9, 1782166952affected
Red HatRed Hat Hardened Imagesgnutls-main, 3.8.13-1.hum1affected
Red HatRed Hat Update Infrastructure 5rhui5/cds-rhel9, 1781525684affected
Red HatRed Hat Update Infrastructure 5rhui5/haproxy-rhel9, 1781525671affected
Red HatRed Hat Update Infrastructure 5rhui5/installer-rhel9, 1781525693affected
Red HatRed Hat Update Infrastructure 5rhui5/rhua-rhel9, 1781525739affected
Red HatRed Hat Enterprise Linux 6gnutlsunknown
Red HatRed Hat Enterprise Linux 7gnutlsaffected
Red HatRed Hat OpenShift Container Platform 4openshift4/ose-hypershift-rhel9unknown
Weakness

CWE details

CWE-193

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

CWE-193 · source CWE mapping

Off-by-one Error

Off-by-one Error represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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