CVE-2026-42945

critical · 9.2

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when the rewrite directive is followed by a rewrite, if, or set directive and an unnamed Perl-Compatible Regular Expression (PCRE) capture (for example, $1, $2) with a replacement string that includes a question mark (?). An unauthenticated attacker along with conditions beyond its control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow 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

68.0%

EPSS (exploit prob.)

99th

EPSS percentile

2026-05-13

Published

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

Weaknesses

CWE-122CWE-131

Affected products

Vendor	Product	Affected versions
f5	dos	>= 4.3.0, <= 4.7.0
f5	dos	4.8.0
f5	nginx_gateway_fabric	>= 1.3.0, <= 1.6.2
f5	nginx_gateway_fabric	>= 2.0.0, <= 2.5.1
f5	nginx_ingress_controller	>= 3.5.0, <= 3.7.2
f5	nginx_ingress_controller	>= 4.0.0, <= 4.0.1
f5	nginx_ingress_controller	>= 5.0.0, <= 5.4.1
f5	nginx_instance_manager	>= 2.16.0, <= 2.21.1
f5	nginx_open_source	>= 0.6.27, <= 1.30.0
f5	nginx_plus	>= r32, <= r36
f5	waf	>= 4.9.0, <= 4.16.0
f5	waf	>= 5.1.0, <= 5.8.0
f5	waf	>= 5.9.0, <= 5.12.1

Check a specific version with /api/v1/cve/match.

References

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-42945