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Vulnerabilities/CVE-2026-42530Public Intelligence Dossier
Source: f5 · Limited verification•Last verified: •Collection Degraded
CVE-2026-42530Unknown / EvaluatingCRITICAL (raw)CVSS 9.2CWE-416

NGINX Open Source has a vulnerability in the ngx_http_v3_module module

Published: 17 Jun 2026•Last updated: 26 Oct 2026, 05:40 PM IST•Source identifier: f5sirt@f5.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
9.2CRITICAL (raw)
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Metric sourcef5sirt@f5.com
EPSS probability
6.2%0.062
Percentile94th
Weakness type
CWE-416
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

NGINX Open Source has a vulnerability in the ngx_http_v3_module module. When NGINX Open Source is configured to use the HTTP/3 QUIC module, a remote unauthenticated attacker along with conditions beyond their control can use a specially crafted HTTP/3 session to reopen a QPACK encoder stream. This may cause a Use-after-Free in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

SOC priority

High Severity / Review

Actively exploited (source statement)

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; CRITICAL severity; Critical source severity without confirmed exploitation

Affected Products & Remediation

4 source-backed products
Affected products and versions (source)
  • f5 nginx gateway fabric · >= 1.3.0 <= 1.6.2; >= 2.0.0 < 2.6.4 · NVD CPE · Source
  • f5 nginx ingress controller · >= 3.5.0 <= 3.7.2; >= 5.0.0 < 5.5.1; 4.0.0; 4.0.1 · NVD CPE · Source
  • f5 nginx instance manager · >= 2.17.0 <= 2.22.0 · NVD CPE · Source
  • f5 nginx open source · >= 1.31.0 < 1.31.2 · 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
f5sirt@f5.com
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*, cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*, cpe:2.3:a:f5:nginx_ingress_controller:4.0.0:*:*:*:*:*:*:*, cpe:2.3:a:f5:nginx_ingress_controller:4.0.1:*:*:*:*:*:*:*, cpe:2.3:a:f5:nginx_instance_manager:*:*:*:*:*:*:*:*, cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*

Evidence & Provenance

3 public sources
my.f5.comSource recordnvd.nist.govSource 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-2026-42530
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-42530
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-42530"| 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

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Correlated briefings

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.