Uncontrolled Memory Allocation in NGINX Open Source and NGINX Plus - CVE-2026-42946
Published: May 14, 2026
Vulnerability identifier: #VU131375
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-42946
CWE-ID: CWE-789
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: F5 Networks
Affected software:
NGINX Open Source
NGINX Plus
NGINX Open Source
NGINX Plus
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose memory contents of the NGINX worker process or cause a denial of service.
The vulnerability exists due to memory allocation with excessive size value and use of out-of-range pointer offset in the ngx_http_scgi_module and ngx_http_uwsgi_module modules when processing responses from an upstream server via scgi_pass or uwsgi_pass. A remote attacker can control responses from an upstream server to disclose memory contents of the NGINX worker process or cause a denial of service.
Exploitation requires man-in-the-middle ability to control responses from an upstream server. There is no control plane exposure; this is a data plane issue only.
How to mitigate CVE-2026-42946
Install security update from vendor's website.