CVE-2026-42530
NGINX Open Source has a vulnerability in the ngx_http_v3_module module.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.82%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- 9.2 CRITICALCVSS: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/M
- EPSS
- 3.82% probability · 89th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- f5/nginx gateway fabric · f5/nginx ingress controller · f5/nginx instance manager · f5/nginx open source
- Source
- f5sirt@f5.com
References
- https://my.f5.com/manage/s/article/K000161616Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:20351
- https://access.redhat.com/security/cve/CVE-2026-42530Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2489872Third Party Advisory
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42530.jsonThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.