Answer in brief
CVE-2026-9256 records a Critical severity (CVSS 8.1) vulnerability in NGINX ngx_http_rewrite_module vulnerability. The current sources do not mark it as known exploited. The current feed maps Red Hat/insights-proxy/insights-proxy-container-rhel9 (generic), F5/NGINX Open Source (generic), F5/NGINX Open Source (generic), F5/NGINX Plus (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Red Hat/insights-proxy/insights-proxy-container-rhel9 (generic), F5/NGINX Open Source (generic), F5/NGINX Open Source (generic), F5/NGINX Plus (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:f5:dos:4.9.0:*:*:*:*:nginx:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:dos:*:*:*:*:*:nginx:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_instance_manager:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_open_source:1.31.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:37.0.0.1:*:*:*:long-term_support:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:*:*:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r32:-:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r32:p1:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r32:p2:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r32:p3:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r32:p4:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r32:p5:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r32:p6:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r36:-:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r36:p1:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r36:p2:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r36:p3:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:nginx_plus:r36:p4:*:*:continuous_releases:*:*:* | Not reported | Not reported |
| cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:discovery:-:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:update_infrastructure:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Red Hat/insights-proxy/insights-proxy-container-rhel9generic | * | Not reported |
| F5/NGINX Open Sourcegeneric | >=1.31.0 <1.31.1 || >=1.30.0 <1.30.2 || 0.1.17 | 1.31.1, 1.30.2 |
| F5/NGINX Open Sourcegeneric | >=1.31.0 <1.31.1 || >=1.30.0 <1.30.2 || >=0.1.17 <=0.9.7 | 1.31.1, 1.30.2 |
| F5/NGINX Plusgeneric | >=37.0 <37.0.1.1 || >=R36 <R36 P5 || >=R32 <R32 P7 | 37.0.1.1, R36 P5, R32 P7 |
Published upstream
May 22, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 15, 2026
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their 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.
Quoted source text, attributed separately from HOL analysis.