Review reviewCritical

CVE-2026-42530

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)...

CVSS: 9.2
EPSS: 3.68%
CISA KEV: Not listed
Published: 2026.06.18

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability3.68%

Technical severityCVSS 9.2

Vulnerability overview

Affected product and versions

Product: F5 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 versions: 2.6.4, 5.5.1, 1.31.2

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that F5 NGINX Open Source, Red Hat Hardened Images, Red Hat Enterprise Linux 10 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: 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
CWE: CWE-416