{"basis":"claimed","id":"CVE-2026-42945","name":"NGINX ngx_http_rewrite_module vulnerability","vendorProject":"F5","product":"NGINX Plus","publishedAt":"2026-05-13","cvss":{"score":9.2,"severity":"CRITICAL","version":"4.0"},"exploited":null,"epss":{"score":0.68047,"percentile":0.99325,"date":"2026-11-02"},"coverage":{"cloudflare":{"status":"blocks","firstOn":"2026-05-15","daysToRule":2},"aws":{"status":"none","firstOn":null,"daysToRule":null},"azure":{"status":"none","firstOn":null,"daysToRule":null},"google":{"status":"none","firstOn":null,"daysToRule":null},"fastly":{"status":"no_history","firstOn":null,"daysToRule":null},"f5":{"status":"rule","firstOn":"2026-07-07","daysToRule":55},"akamai":{"status":"no_source","firstOn":null,"daysToRule":null},"crs":{"status":"none","firstOn":null,"daysToRule":null}},"title":"NGINX ngx_http_rewrite_module vulnerability","description":"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.","cwes":["CWE-122"],"vendors":[{"vendor":"cloudflare","status":"blocks","basis":"claimed","firstOn":"2026-05-15","firstIsNew":true,"daysToRule":2,"daysAtMost":null,"freePlan":false,"claims":[{"id":"296183c3061c60374c0b877f2045e621dd94bfd4b892375dd3aeb95b2cb36487","cve_id":"CVE-2026-42945","vendor":"cloudflare","product":"Cloudflare Managed Ruleset","rule_id":"2013e3e58efe4b79a26e214f7e52be73","rule_name":"nginx - Remote Code Execution - Buffer Overread - CVE:CVE-2026-42945","change":"new","default_action":"Block","published_on":"2026-05-15","source_url":"https://developers.cloudflare.com/changelog/post/2026-05-15-emergency-waf-release/","source_title":"WAF Release - 2026-05-15 - Emergency","excerpt":"nginx - Remote Code Execution - Buffer Overread - CVE:CVE-2026-42945. Previous action: N/A. New action: Block. This is a new detection.","first_seen_at":"2026-11-02T21:00:15.584Z"},{"id":"df5e04569e7c2a90fdfb4241c20bae8908e9b5f538ea89b4727477051f7c94da","cve_id":"CVE-2026-42945","vendor":"cloudflare","product":"Cloudflare Managed Ruleset","rule_id":"68226e83a4d14ee9a9c878469df0ee6c","rule_name":"nginx - Remote Code Execution - Heap Spray - CVE:CVE-2026-42945","change":"new","default_action":"Block","published_on":"2026-05-15","source_url":"https://developers.cloudflare.com/changelog/post/2026-05-15-emergency-waf-release/","source_title":"WAF Release - 2026-05-15 - Emergency","excerpt":"nginx - Remote Code Execution - Heap Spray - CVE:CVE-2026-42945. Previous action: N/A. New action: Block. This is a new detection.","first_seen_at":"2026-11-02T21:00:15.584Z"}]},{"vendor":"aws","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"azure","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"google","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"fastly","status":"no_history","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"f5","status":"rule","basis":"claimed","firstOn":"2026-07-07","firstIsNew":true,"daysToRule":55,"daysAtMost":null,"freePlan":false,"claims":[{"id":"603a05f30f91e2d7a0b47f4a04791f22511f9703d78d177b8bea88514d612854","cve_id":"CVE-2026-42945","vendor":"f5","product":"Attack signatures","rule_id":"200011109","rule_name":"Nginx Rift Buffer Overflow","change":"new","default_action":null,"published_on":"2026-07-07","source_url":"https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog","source_title":"F5 Distributed Cloud attack signatures changelog","excerpt":"Added: signature 200011109 \"Nginx Rift Buffer Overflow\" (Buffer Overflow, risk Low), systems: Nginx. References: CVE-2026-42945.","first_seen_at":"2026-11-02T21:00:24.693Z"}]},{"vendor":"akamai","status":"no_source","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"crs","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]}],"updatedAt":"2026-11-02T21:00:31.242Z","cvssVector":"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","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total"},"measured":[],"social":{"total":1,"first_seen":"2026-11-02T12:20:43.000Z","daily":[{"day":"2026-10-20","posts":0},{"day":"2026-10-21","posts":0},{"day":"2026-10-22","posts":0},{"day":"2026-10-23","posts":0},{"day":"2026-10-24","posts":0},{"day":"2026-10-25","posts":0},{"day":"2026-10-26","posts":0},{"day":"2026-10-27","posts":0},{"day":"2026-10-28","posts":0},{"day":"2026-10-29","posts":0},{"day":"2026-10-30","posts":0},{"day":"2026-10-31","posts":0},{"day":"2026-11-01","posts":0},{"day":"2026-11-02","posts":1}],"top_posts":[],"exploit_repositories":[{"source":"github","kind":"poc","url":"https://github.com/basesixtythree/B63-POC-CVE-2026-42945","author":"basesixtythree","author_name":null,"avatar_url":"https://avatars.githubusercontent.com/u/220976450?v=4","text":"basesixtythree/B63-POC-CVE-2026-42945: PoC and verification material for CVE-2026-42945 (CWE-122 heap overflow in ngx_http_rewrite_module -> attacker-shaped cleanup hijack -> system() RCE in the ASLR-off worker; patched-twin negative + 5/5 reliability captured in the shipped lab)","engagement":0,"posted_at":"2026-11-02T12:20:43.000Z"}]}}