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CVE-2026-42945

NGINX ngx_http_rewrite_module vulnerability

CVSS 3.1 8.1 HIGHCVSS 4.0 9.2 CRITICALCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-42945

Published

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.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-42945

Published

NGINX Plus

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "F5",
                    "product": "NGINX Plus",
                    "modules": [
                        "ngx_http_rewrite_module"
                    ],
                    "versions": [
                        {
                            "status": "unaffected",
                            "version": "R37",
                            "lessThan": "*",
                            "versionType": "custom"
                        },
                        {
                            "status": "affected",
                            "version": "R36",
                            "lessThan": "R36 P4",
                            "versionType": "custom"
                        },
                        {
                            "status": "affected",
                            "version": "R32",
                            "lessThan": "R32 P6",
                            "versionType": "custom"
                        }
                    ],
                    "defaultStatus": "unknown"
                }

NGINX Open Source

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "F5",
                    "product": "NGINX Open Source",
                    "modules": [
                        "ngx_http_rewrite_module"
                    ],
                    "versions": [
                        {
                            "status": "unaffected",
                            "version": "1.31.0",
                            "lessThan": "*",
                            "versionType": "semver"
                        },
                        {
                            "status": "affected",
                            "version": "0.6.27",
                            "lessThan": "1.30.1",
                            "versionType": "semver"
                        }
                    ],
                    "defaultStatus": "unaffected"
                }

Original source record · Cite this exact observation · Complete original publisher JSON