{"id":"CVE-2026-33534","summary":"EspoCRM has authenticated SSRF via internal-host validation bypass using alternative IPv4 notation","details":"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.","aliases":["GHSA-h7gx-8gwv-7g73"],"modified":"2026-07-08T08:13:19.303093Z","published":"2026-04-13T19:20:04.414Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33534.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-918"]},"references":[{"type":"WEB","url":"https://github.com/espocrm/espocrm/releases/tag/9.3.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33534.json"},{"type":"ADVISORY","url":"https://github.com/espocrm/espocrm/security/advisories/GHSA-h7gx-8gwv-7g73"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33534"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/espocrm/espocrm","events":[{"introduced":"0"},{"fixed":"f1763e732f34fbebf7f70f176eec1ccd8a272679"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"9.3.4"}],"source":["AFFECTED_FIELD","CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:espocrm:espocrm:*:*:*:*:*:*:*:*"}}],"versions":["9.3.3","9.3.2","9.3.1","9.3.0","9.2.0","9.1.0","9.0.2","9.0.1","9.0.0","8.4.0","8.2.0","8.1.0","8.0.2","8.0.1","8.0.0","7.4.3","7.4.2","7.4.1","7.4.0","7.3.0","7.2.0","7.1.3","7.1.2","7.1.1","7.1.0","7.0.8","7.0.7","7.0.6","7.0.5","7.0.4","7.0.3","7.0.2","7.0.1","7.0.0","6.0.1","6.0.0","6.0.0-beta4","6.0.0-beta2","6.0.0-beta1","5.9.2","5.9.1","5.9.0","5.8.2","5.8.1","5.8.0","5.7.5","5.7.4","5.7.3","5.7.2","5.7.1","5.7.0","5.6.1","5.6.0","5.5.1","5.5.0","5.4.3","5.4.2","5.4.1","5.4.0","5.3.2","5.3.1","5.3.0","5.2.5","5.2.4","5.2.3","5.2.2","5.2.1","5.2.0","5.1.2","5.1.1","5.1.0","5.0.1","5.0.0","4.8.0","4.7.0","4.6.0","4.5.0","4.4.0","4.3.0","4.3.0-beta.2","4.3.0-beta.1","4.2.4","4.2.3","4.2.2","4.2.1","4.2.0","4.1.4","4.1.3","4.1.2","4.1.1","4.1.0","4.0.3","4.0.2","4.0.1","4.0.0","4.0.0-beta.4","4.0.0-beta.3","4.0.0-beta.2","4.0.0-beta.1","3.9.1","3.9.0","3.8.0","3.7.1","3.7.0","3.6.1","3.6.0","3.5.0","3.4.2","3.4.1","3.4.0","3.3.0","3.2.0","3.1.0","3.0.0","2.9.0","2.8.1","2.8.0","2.6.0","2.5.2","2.5.1","2.5.0","2.4.0","2.3.0","2.0.1","1.2.0","1.1.2","1.1.1","1.1.0","1.0.1","1.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33534.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"}]}