{"id":"CVE-2026-93483","state":"PUBLISHED","title":"In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain unauthorized access to sensitive system functions by manipulating a specific HTTP request","description":"In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain unauthorized access to sensitive system functions by manipulating a specific HTTP request header. Because the application incorrectly trusts this header, an attacker can impersonate any user, including administrators, without requiring a password. This grants full access to confidential data and system controls. More specifically, the HTTPBasicAuth modules for the agent (Kernel::System::Auth::HTTPBasicAuth) and customer (Kernel::System::CustomerAuth::HTTPBasicAuth) interfaces read the username to log in not only from $ENV{REMOTE_USER} (set by the web server after successful authentication), but also, as a fallback, from $ENV{HTTP_REMOTE_USER}, which is populated directly from an attacker-controllable \"Remote-User\" request header. On systems where HTTPBasicAuth was configured as the authentication backend, this allowed an attacker to log in as any existing user by sending a request with a forged Remote-User header, without providing any credentials.","publishedAt":"2026-10-15T03:43:10.406Z","updatedAt":"2026-10-19T18:42:25.087Z","severity":{"score":9.5,"label":"Critical","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/AU:Y/R:U/RE:L/U:Red","source":"mitre"},"assigner":"mitre","products":["Znuny Znuny"],"affected":[{"vendor":"Znuny","product":"Znuny","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"6.5.25","versionType":"semver"},{"version":"7.0.0","status":"affected","lessThan":"7.3.7","versionType":"semver"}],"repo":"https://github.com/znuny/znuny"}],"references":["https://www.znuny.org/advisories","https://www.znuny.org/en/advisories/zsa-2026-14"],"weaknesses":["CWE-348"],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/93xxx/CVE-2026-93483.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93483","state":"PUBLISHED","datePublished":"2026-10-15T03:43:10.406Z","dateUpdated":"2026-10-19T18:42:25.087Z","assignerShortName":"mitre","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateReserved":"2026-09-18T04:33:42.990Z"},"containers":{"cna":{"descriptions":[{"lang":"en","value":"In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain unauthorized access to sensitive system functions by manipulating a specific HTTP request header. Because the application incorrectly trusts this header, an attacker can impersonate any user, including administrators, without requiring a password. This grants full access to confidential data and system controls. More specifically, the HTTPBasicAuth modules for the agent (Kernel::System::Auth::HTTPBasicAuth) and customer (Kernel::System::CustomerAuth::HTTPBasicAuth) interfaces read the username to log in not only from $ENV{REMOTE_USER} (set by the web server after successful authentication), but also, as a fallback, from $ENV{HTTP_REMOTE_USER}, which is populated directly from an attacker-controllable \"Remote-User\" request header. On systems where HTTPBasicAuth was configured as the authentication backend, this allowed an attacker to log in as any existing user by sending a request with a forged Remote-User header, without providing any credentials."}],"affected":[{"vendor":"Znuny","product":"Znuny","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"6.5.25","versionType":"semver"},{"version":"7.0.0","status":"affected","lessThan":"7.3.7","versionType":"semver"}],"repo":"https://github.com/znuny/znuny"}],"references":[{"url":"https://www.znuny.org/advisories"},{"url":"https://www.znuny.org/en/advisories/zsa-2026-14"}],"metrics":[{"cvssV4_0":{"Automatable":"YES","Recovery":"USER","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":9.5,"baseSeverity":"CRITICAL","privilegesRequired":"NONE","providerUrgency":"RED","subAvailabilityImpact":"LOW","subConfidentialityImpact":"HIGH","subIntegrityImpact":"HIGH","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/AU:Y/R:U/RE:L/U:Red","version":"4.0","vulnAvailabilityImpact":"LOW","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnerabilityResponseEffort":"LOW"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-348","description":"CWE-348 Use of Less Trusted Source","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"mitre","orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateUpdated":"2026-10-15T03:43:10.406Z"},"x_generator":{"engine":"CVE-Request-form 0.0.1"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:znuny:znuny:*:*:*:*:*:*:*:*","versionEndExcluding":"6.5.25"},{"vulnerable":true,"criteria":"cpe:2.3:a:znuny:znuny:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.0","versionEndExcluding":"7.3.7"}]}]}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-19T18:36:30.445045Z","id":"CVE-2026-93483","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T18:42:25.087Z"}}]}}}