CVE-2026-42926: NGINX ngx_http_proxy_v2_module vulnerability

Severity: medium (CVSS 5.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-13 · updated 2026-10-26
Weakness: CWE-172

Description

When NGINX Open Source is configured to proxy HTTP/2 traffic by setting proxy_http_version to 2, and also uses proxy_set_body, an attacker may be able to inject frame headers and payload bytes to the upstream peer. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Affected products

F5 NGINX Gateway Fabric: from 1.3.0 through 1.6.2; from 2.0.0 through 2.6.0
F5 NGINX Ingress Controller: from 3.5.0 through 3.7.2; from 4.0.0 through 4.0.1; from 5.0.0 through 5.4.2
F5 NGINX Instance Manager: from 2.16.0 through 2.22.0
F5 NGINX Open Source: from 1.29.4 through 1.30.0

References

https://my.f5.com/manage/s/article/K000161131

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