{"basis":"claimed","id":"CVE-2025-34027","name":"Versa Concerto Authentication Bypass File Write Remote Code Execution","vendorProject":"Versa","product":"Concerto","publishedAt":"2025-05-21","cvss":{"score":10,"severity":"CRITICAL","version":"4.0"},"exploited":null,"epss":{"score":0.46402,"percentile":0.9882,"date":"2026-11-02"},"coverage":{"cloudflare":{"status":"blocks","firstOn":"2025-06-02","daysToRule":12},"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":"2025-08-15","daysToRule":86},"akamai":{"status":"no_source","firstOn":null,"daysToRule":null},"crs":{"status":"none","firstOn":null,"daysToRule":null}},"title":"Versa Concerto Authentication Bypass File Write Remote Code Execution","description":"The Versa Concerto SD-WAN orchestration platform is vulnerable to an authentication bypass in the Traefik reverse proxy configuration, allowing at attacker to access administrative endpoints. The Spack upload endpoint can be leveraged for a Time-of-Check to Time-of-Use (TOCTOU) write in combination with a race condition to achieve remote code execution via path loading manipulation, allowing an unauthenticated actor to achieve remote code execution (RCE).This issue is known to affect Concerto from 12.1.2 through 12.2.0. Additional versions may be vulnerable.","cwes":["CWE-367"],"vendors":[{"vendor":"cloudflare","status":"blocks","basis":"claimed","firstOn":"2025-06-02","firstIsNew":true,"daysToRule":12,"daysAtMost":null,"freePlan":false,"claims":[{"id":"f43ee4c13843c58dcddef9222150b60d9ea538c7bba3feb8a69b27437305755a","cve_id":"CVE-2025-34027","vendor":"cloudflare","product":"Cloudflare Managed Ruleset","rule_id":"752cfb5e6f9c46f0953c742139b52f02","rule_name":"Versa Concerto SD-WAN - Auth Bypass - CVE:CVE-2025-34027","change":"new","default_action":"Block","published_on":"2025-06-02","source_url":"https://developers.cloudflare.com/changelog/post/2025-06-02-waf-release/","source_title":"WAF Release - 2025-06-02","excerpt":"Versa Concerto SD-WAN - Auth Bypass - CVE:CVE-2025-34027. Previous action: Log. New action: Block. This is a New Detection","first_seen_at":"2026-11-02T21:00:16.558Z"}]},{"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":"2025-08-15","firstIsNew":true,"daysToRule":86,"daysAtMost":null,"freePlan":false,"claims":[{"id":"655d86cd5f996d66a7c197d72f2421845f319ff0ebf696c0c9561fa2301728ae","cve_id":"CVE-2025-34027","vendor":"f5","product":"Attack signatures","rule_id":"200013125","rule_name":"Versa Concerto Authentication Bypass","change":"new","default_action":null,"published_on":"2025-08-15","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 200013125 \"Versa Concerto Authentication Bypass\" (Authentication/Authorization Attacks, risk High), systems: Other Web Server. References: CVE-2025-34027.","first_seen_at":"2026-11-02T21:00:25.702Z"}]},{"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":"2026-11-02T21:16:34.613Z","cvssVector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L","ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total"},"measured":[{"engineId":"owasp-crs","engineName":"OWASP Core Rule Set","engineVersion":"4.25.0","runtime":"Coraza v3.8.1","config":"paranoia level 1, anomaly threshold 5, default CRS settings","ranAt":"2026-11-02T13:02:57.000Z","verdict":"passed","templateId":"CVE-2025-34027","templatePath":"http/cves/2025/CVE-2025-34027.yaml","requests":1,"blockedRequests":0,"rules":[],"note":"","requestDetail":[{"method":"GET","path":"/portalapi/v1/roles/option;%2fv1%2fping","status":200,"blocked":false,"rules":[]}]},{"engineId":"owasp-crs","engineName":"OWASP Core Rule Set","engineVersion":"4.25.0","runtime":"Coraza v3.8.1","config":"paranoia level 2, anomaly threshold 5, default CRS settings","ranAt":"2026-11-02T13:03:28.000Z","verdict":"passed","templateId":"CVE-2025-34027","templatePath":"http/cves/2025/CVE-2025-34027.yaml","requests":1,"blockedRequests":0,"rules":[],"note":"","requestDetail":[{"method":"GET","path":"/portalapi/v1/roles/option;%2fv1%2fping","status":200,"blocked":false,"rules":[]}]}],"social":{"total":0,"first_seen":null,"daily":[{"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":0},{"day":"2026-11-03","posts":0}],"top_posts":[],"exploit_repositories":[]}}