CVE-2026-33534— EspoCRM has authenticated SSRF via internal-host validation bypass using alternative IPv4 notation

EspoCRM has authenticated SSRF via internal-host validation bypass using alternative IPv4 notation

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.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

服务端请求伪造(SSRF)

EspoCRM 代码问题漏洞

EspoCRM是EspoCRM开源的一套开源的基于Web的客户关系管理系统（CRM）。该系统提供销售自动化、社区和客户支持等功能。 EspoCRM 9.3.3及之前版本存在代码问题漏洞，该漏洞源于HostCheck::isNotInternalHost函数依赖的PHP filter_var函数无法识别替代IPv4表示法，可能导致服务端请求伪造攻击。

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