{"id":"CVE-2026-33534","state":"PUBLISHED","title":"EspoCRM has authenticated SSRF via internal-host validation bypass using alternative IPv4 notation","description":"EspoCRM is an open source customer relationship management application. Versions 9.3.3 and below have an authenticated Server-Side Request Forgery (SSRF) vulnerability that allows bypassing the internal-host validation logic by using alternative IPv4 representations such as octal notation (e.g., 0177.0.0.1 instead of 127.0.0.1). This is caused by HostCheck::isNotInternalHost() function relying on PHP's filter_var(..., FILTER_VALIDATE_IP), which does not recognize alternative IP formats, causing the validation to fall through to a DNS lookup that returns no records and incorrectly treats the host as safe, however the cURL subsequently normalizes the address and connects to the loopback destination. Through the confirmed /api/v1/Attachment/fromImageUrl endpoint, an authenticated user can force the server to make requests to loopback-only services and store the fetched response as an attachment. This vulnerability is distinct from CVE-2023-46736 (which involved redirect-based SSRF) and may allow access to internal resources reachable from the application runtime. This issue has been fixed in version 9.3.4.","publishedAt":"2026-04-13T19:20:04.414Z","updatedAt":"2026-04-14T16:28:58.299Z","severity":{"score":4.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["espocrm espocrm"],"affected":[{"vendor":"espocrm","product":"espocrm","versions":[{"version":"< 9.3.4","status":"affected"}]}],"references":["https://github.com/espocrm/espocrm/security/advisories/GHSA-h7gx-8gwv-7g73","https://github.com/espocrm/espocrm/releases/tag/9.3.4"],"weaknesses":["CWE-918"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/33xxx/CVE-2026-33534.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-33534","state":"PUBLISHED","datePublished":"2026-04-13T19:20:04.414Z","dateUpdated":"2026-04-14T16:28:58.299Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-03-20T18:05:11.831Z"},"containers":{"cna":{"title":"EspoCRM has authenticated SSRF via internal-host validation bypass using alternative IPv4 notation","descriptions":[{"lang":"en","value":"EspoCRM is an open source customer relationship management application. Versions 9.3.3 and below have an authenticated Server-Side Request Forgery (SSRF) vulnerability that allows bypassing the internal-host validation logic by using alternative IPv4 representations such as octal notation (e.g., 0177.0.0.1 instead of 127.0.0.1). This is caused by HostCheck::isNotInternalHost() function relying on PHP's filter_var(..., FILTER_VALIDATE_IP), which does not recognize alternative IP formats, causing the validation to fall through to a DNS lookup that returns no records and incorrectly treats the host as safe, however the cURL subsequently normalizes the address and connects to the loopback destination. Through the confirmed /api/v1/Attachment/fromImageUrl endpoint, an authenticated user can force the server to make requests to loopback-only services and store the fetched response as an attachment. This vulnerability is distinct from CVE-2023-46736 (which involved redirect-based SSRF) and may allow access to internal resources reachable from the application runtime. This issue has been fixed in version 9.3.4."}],"affected":[{"vendor":"espocrm","product":"espocrm","versions":[{"version":"< 9.3.4","status":"affected"}]}],"references":[{"url":"https://github.com/espocrm/espocrm/security/advisories/GHSA-h7gx-8gwv-7g73","name":"https://github.com/espocrm/espocrm/security/advisories/GHSA-h7gx-8gwv-7g73","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/espocrm/espocrm/releases/tag/9.3.4","name":"https://github.com/espocrm/espocrm/releases/tag/9.3.4","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.3,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-13T19:20:04.414Z"},"source":{"advisory":"GHSA-h7gx-8gwv-7g73","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/espocrm/espocrm/security/advisories/GHSA-h7gx-8gwv-7g73","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-14T15:28:00.570907Z","id":"CVE-2026-33534","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-14T16:28:58.299Z"}}]}}}