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Vulnerabilities/CVE-2026-42009Public Intelligence Dossier
Source: gnu · Limited verification•Last verified: •Collection Running
CVE-2026-42009Unknown / EvaluatingHIGH (raw)CVSS 7.5CWE-475

A flaw was found in gnutls

Published: 18 May 2026•Last updated: 15 Oct 2026, 01:47 AM IST•Source identifier: secalert@redhat.com
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
7.5HIGH (raw)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Metric sourcesecalert@redhat.com
EPSS probability
1.1%0.011
Percentile66th
Weakness type
CWE-475
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security (DTLS) packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets with duplicate sequence numbers. This could lead to unstable packet ordering or undefined behavior, resulting in a denial of service.

SOC priority

High

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; HIGH severity; No confirmed exploitation signal in current enrichment

Affected Products & Remediation

14 source-backed products
Affected products and versions (source)
  • gnu gnutls · version range not provided by source · NVD CPE · Source
  • redhat hardened images · version range not provided by source · NVD CPE · Source
  • redhat openshift container platform · 4.0 · NVD CPE · Source
  • redhat enterprise linux · 6.0; 7.0; 8.0; for els 8.10; for ibm z systems 8.0 s390x; for ibm z systems els 8.10; for power little endian 8.0 ppc64le; for power little endian els 8.10; 9.0; 9.8; for els 9.8; for eus 9.8; for ibm z systems 9.0 s390x; for ibm z systems els 9.8; for ibm z systems eus 9.8; for power little endian 9.0 ppc64le; for power little endian els 9.8; for power little endian eus 9.8; for update services for sap solutions 9.8; server for power little endian update services for sap solutions 9.8; 10.0; 10.2; for els 10.2; for eus 10.2; for ibm z systems 10.2; for ibm z systems els 10.2; for ibm z systems eus 10.2; for power little endian 10.0; for power little endian 10.2; for power little endian els 10.2; for power little endian eus 10.2 · NVD CPE · Source
  • redhat enterprise linux for els · 8.10; 9.8; 10.2 · NVD CPE · Source
  • redhat enterprise linux for ibm z systems · 8.0 s390x; els 8.10; 9.0 s390x; els 9.8; eus 9.8; 10.2; els 10.2; eus 10.2 · NVD CPE · Source
  • redhat enterprise linux for ibm z systems els · 8.10; 9.8; 10.2 · NVD CPE · Source
  • redhat enterprise linux for power little endian · 8.0 ppc64le; els 8.10; 9.0 ppc64le; els 9.8; eus 9.8; 10.0; 10.2; els 10.2; eus 10.2 · NVD CPE · Source
  • redhat enterprise linux for power little endian els · 8.10; 9.8; 10.2 · NVD CPE · Source
  • redhat enterprise linux for eus · 9.8; 10.2 · NVD CPE · Source
  • redhat enterprise linux for ibm z systems eus · 9.8; 10.2 · NVD CPE · Source
  • redhat enterprise linux for power little endian eus · 9.8; 10.2 · NVD CPE · Source
  • redhat enterprise linux for update services for sap solutions · 9.8 · NVD CPE · Source
  • redhat enterprise linux server for power little endian update services for sap solutions · 9.8 · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched network-unauthenticated (CVSS AV:N, CVSS PR:N, CVSS UI:N)

Exposure

  1. Identify devices reporting this CVE and note which expose the affected service to untrusted networks.Telemetry: DeviceTvmSoftwareVulnerabilities · A network-reachable, no-privilege vector makes internet-facing instances the first exposure question. · Rule network-unauthenticated

Exploitation evidence

  1. Review inbound connections to the affected service from unexpected sources since the advisory date.Telemetry: DeviceNetworkEvents · Hunting hypothesis from the CVSS vector; it does not show that exploitation occurred. · Rule network-unauthenticated

Response

  1. Confirm the source-stated update is installed and the CVE is no longer reported.Telemetry: DeviceTvmSoftwareVulnerabilities · A follow-up inventory check verifies remediation. · Rule network-unauthenticated

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
secalert@redhat.com
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:gnu:gnutls:-:*:*:*:*:*:*:*, cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:*, cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*, cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*, cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*, cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:arm64:*, cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:x64:*, cpe:2.3:o:redhat:enterprise_linux_for_els:8.10:*:*:*:*:*:arm64:*, cpe:2.3:o:redhat:enterprise_linux_for_els:8.10:*:*:*:*:*:x64:*, cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0_s390x:*:*:*:*:*:*:*

Evidence & Provenance

3 public sources
nvd.nist.govSource recordaccess.redhat.comSource recordaccess.redhat.comSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-42009
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-42009
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-42009"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.