CVE-2026-42530 remediation guide

F5 NGINX Open Source, Red Hat Hardened Images, Red Hat Enterprise Linux 10

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)...

Open CVE record

ProductF5 NGINX Open Source, Red Hat Hardened Images, Red Hat Enterprise Linux 10

Affected versions>= 1.31.0 < 1.31.2, >= 1.3.0 <= 1.6.2, >= 2.0.0 < 2.6.4, >= 3.5.0 <= 3.7.2, >= 5.0.0 < 5.5.1, 4.0.0, 4.0.1, >= 2.17.0 <= 2.22.0

Fixed versions2.6.4, 5.5.1, 1.31.2

Priority basisReview · CVSS 9.2 · EPSS 3.68%

Identify the affected asset

Confirm whether F5 NGINX Open Source, Red Hat Hardened Images, Red Hat Enterprise Linux 10 is installed, record the deployed version and installation path, and identify exposed interfaces.

Record the product name, package or appliance identifier, and installed version.
Identify internet-facing, administrative, API, and internal access paths.
Preserve the pre-change configuration and relevant service logs.

Validate the affected-version match

Compare the deployed version with the affected range: >= 1.31.0 < 1.31.2, >= 1.3.0 <= 1.6.2, >= 2.0.0 < 2.6.4, >= 3.5.0 <= 3.7.2, >= 5.0.0 < 5.5.1, 4.0.0, 4.0.1, >= 2.17.0 <= 2.22.0. Treat incomplete inventory results as unresolved.

Prioritize with independent signals

The CVSS severity warrants an early asset and exposure review. Combine this signal with asset criticality, exposure, compensating controls, and business impact.

Apply supported remediation

Follow the vendor advisory or supported update path. Current fixed-version status: 2.6.4, 5.5.1, 1.31.2. Preserve configuration and rollback material before change.

Verify the result

Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.

Confirm the expected version and package state.
Run a functional health check for critical service paths.
Review authentication, error, application, and security monitoring logs.
Reassess exposure if the supported fix cannot be applied.

Operational boundary

This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.