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Vulnerability record · CVE-2026-42530 · published 17 June 2026

CVE-2026-42530: F5 nginx gateway fabric use after free vulnerability

F5 · Nginx Gateway Fabric

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.

9.2 CVSS 4.0 Critical EPSS 1.1% · top 34.6% CWE-416 · Use after free
9.2CVSS 4.0 base score
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
4Affected product versions listed by NVD
5References
16 Jul 2026Last modified by NVD

Description

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.

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:

Affected products

4 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://my.f5.com/manage/s/article/K000161616 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:20351
https://access.redhat.com/security/cve/CVE-2026-42530 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2489872 Third Party Advisory
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42530.json Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-42530), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.