{"id":61635,"date":"2026-06-10T10:27:38","date_gmt":"2026-06-10T10:27:38","guid":{"rendered":"https:\/\/zero.redgem.net\/?p=61635"},"modified":"2026-06-10T10:27:38","modified_gmt":"2026-06-10T10:27:38","slug":"roxy-wi-authenticated-arbitrary-file-write-on-every-managed-load-balancer-and-downstream-rce-via-waf","status":"publish","type":"post","link":"https:\/\/zero.redgem.net\/?p=61635","title":{"rendered":"Roxy-WI: Authenticated arbitrary file write on every managed load balancer (and downstream RCE) via WAF rule save `config_file_name`_CVE-2026-45556"},"content":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Roxy-WI is a web interface for managing Haproxy, Nginx, Apache and Keepalived servers. In versions 8.2.6.4 and prior, POST \/waf\/\\u003cservice\\u003e\/\\u003cserver_ip\\u003e\/rule\/\\u003crule_id\\u003e\/save accepts a config_file_name form field that is passed straight through to config_mod.master_slave_upload_and_restart(&#8230;) as the destination path. The validation chain (_replace_config_path_to_correct \u2192 check_is_conf) only requires the path to contain a hard-coded service substring (nginx\/haproxy\/apache2\/httpd\/keepalived) and the substring conf or cfg, and to not contain &#8230; The encoded-slash substitution 92 \u2192 \/ is applied before the substring check, so the attacker can build any absolute path anywhere on the LB filesystem as long as it satisfies those substring constraints. The body of the WAF rule (config form field) is written verbatim to that path. By choosing a filename like 92etc92cron.d92nginx_cfg_evil (resolving to \/etc\/cron.d\/nginx_cfg_evil), an attacker drops a cron entry on the load balancer with attacker-controlled content. Cron parses the file on its next scan, executing the embedded job as root \u2014 full RCE on every load balancer the caller&#8217;s group manages. At time of publication, there are no publicly available patches.&#8221;,&#8221;published&#8221;:&#8221;2026-06-10T14:00:54.973Z&#8221;,&#8221;modified&#8221;:&#8221;2026-06-10T14:00:54.973Z&#8221;,&#8221;type&#8221;:&#8221;cve&#8221;,&#8221;title&#8221;:&#8221;Roxy-WI: Authenticated arbitrary file write on every managed load balancer (and downstream RCE) via WAF rule save `config_file_name`&#8221;,&#8221;source&#8221;:&#8221;GitHub_M&#8221;,&#8221;references&#8221;:&#8221;https:\/\/github.com\/roxy-wi\/roxy-wi\/security\/advisories\/GHSA-85gm-773v-x7m4&#8243;,&#8221;id&#8221;:&#8221;CVE-2026-45556&#8243;,&#8221;bulletinFamily&#8221;:&#8221;&#8221;,&#8221;cwe&#8221;:[&#8220;CWE-20&#8243;,&#8221;CWE-22&#8243;,&#8221;CWE-73&#8243;,&#8221;CWE-78&#8243;],&#8221;cvelist&#8221;:null,&#8221;sourceData&#8221;:&#8221;roxy-wi roxy-wi \\u003c= 8.2.6.4&#8243;,&#8221;sourceHref&#8221;:&#8221;&#8221;,&#8221;cvss&#8221;:{&#8220;score&#8221;:9.9,&#8221;severity&#8221;:&#8221;CRITICAL&#8221;,&#8221;vector&#8221;:&#8221;CVSS:3.1\/AV:N\/AC:L\/PR:L\/UI:N\/S:C\/C:H\/I:H\/A:H&#8221;,&#8221;version&#8221;:&#8221;3.1&#8243;},&#8221;cvss2&#8243;:{},&#8221;cvss3&#8243;:{&#8220;version&#8221;:&#8221;&#8221;,&#8221;vectorString&#8221;:&#8221;&#8221;,&#8221;baseScore&#8221;:0,&#8221;baseSeverity&#8221;:&#8221;&#8221;,&#8221;attackVector&#8221;:&#8221;&#8221;,&#8221;attackComplexity&#8221;:&#8221;&#8221;,&#8221;privilegesRequired&#8221;:&#8221;&#8221;,&#8221;userInteraction&#8221;:&#8221;&#8221;,&#8221;scope&#8221;:&#8221;&#8221;,&#8221;confidentialityImpact&#8221;:&#8221;&#8221;,&#8221;integrityImpact&#8221;:&#8221;&#8221;,&#8221;availabilityImpact&#8221;:&#8221;&#8221;,&#8221;cvssV3&#8243;:{&#8220;version&#8221;:&#8221;&#8221;,&#8221;vectorString&#8221;:&#8221;&#8221;,&#8221;baseScore&#8221;:0,&#8221;baseSeverity&#8221;:&#8221;&#8221;,&#8221;attackVector&#8221;:&#8221;&#8221;,&#8221;attackComplexity&#8221;:&#8221;&#8221;,&#8221;privilegesRequired&#8221;:&#8221;&#8221;,&#8221;userInteraction&#8221;:&#8221;&#8221;,&#8221;scope&#8221;:&#8221;&#8221;,&#8221;confidentialityImpact&#8221;:&#8221;&#8221;,&#8221;integrityImpact&#8221;:&#8221;&#8221;,&#8221;availabilityImpact&#8221;:&#8221;&#8221;}},&#8221;href&#8221;:&#8221;&#8221;,&#8221;category_name&#8221;:&#8221;CVE&#8221;,&#8221;post_link&#8221;:&#8221;&#8221;,&#8221;product&#8221;:&#8221;roxy-wi&#8221;,&#8221;version&#8221;:&#8221;\\u003c= 8.2.6.4&#8243;,&#8221;vendor&#8221;:&#8221;roxy-wi&#8221;,&#8221;ai_description&#8221;:&#8221;Authenticated arbitrary file write on every managed load balancer via WAF rule save, leading to full RCE&#8221;,&#8221;ai_severity&#8221;:&#8221;Critical&#8221;,&#8221;ai_vendor&#8221;:&#8221;Roxy-WI&#8221;,&#8221;ai_product&#8221;:&#8221;Roxy-WI&#8221;,&#8221;ai_version&#8221;:&#8221;\\u003c= 8.2.6.4&#8243;,&#8221;ai_score&#8221;:9.9}<\/p>\n","protected":false},"excerpt":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Roxy-WI is a web interface for managing Haproxy, Nginx, Apache and Keepalived servers. In versions 8.2.6.4 and prior, POST \/waf\/\\u003cservice\\u003e\/\\u003cserver_ip\\u003e\/rule\/\\u003crule_id\\u003e\/save accepts a config_file_name form field&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[9,6,8,45,12,13,7,11,5],"class_list":["post-61635","post","type-post","status-publish","format-standard","hentry","category-category_cve","tag-critical","tag-cve","tag-cvss","tag-cvss-99","tag-exploit","tag-news","tag-security","tag-tapic","tag-vulnerability"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Roxy-WI: Authenticated arbitrary file write on every managed load balancer (and downstream RCE) via WAF rule save `config_file_name`_CVE-2026-45556 - zero redgem<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/zero.redgem.net\/?p=61635\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Roxy-WI: Authenticated arbitrary file write on every managed load balancer (and downstream RCE) via WAF rule save `config_file_name`_CVE-2026-45556 - zero redgem\" \/>\n<meta property=\"og:description\" content=\"{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Roxy-WI is a web interface for managing Haproxy, Nginx, Apache and Keepalived servers. 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