CVE-2026-33656
Published: 22 April 2026
Summary
CVE-2026-33656 is a critical-severity Path Traversal (CWE-22) vulnerability in Espocrm Espocrm. Its CVSS base score is 9.1 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 38.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and AC-6 (Least Privilege).
Deeper analysis
CVE-2026-33656 is a path traversal vulnerability (CWE-22) affecting EspoCRM, an open source customer relationship management application, in versions prior to 9.3.4. The issue stems from the built-in formula scripting engine, which allows updating the `sourceId` field on `Attachment` entities. This `sourceId` value is concatenated directly into file paths without sanitization in the `EspoUploadDir::getFilePath()` function, enabling redirection of file read or write operations to arbitrary paths within the web server's `open_basedir` scope. The vulnerability has a CVSS v3.1 base score of 9.1 (AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H).
An authenticated administrator can exploit this vulnerability remotely with low complexity and no user interaction required. By overwriting the `sourceId` field via the formula scripting engine, the attacker can manipulate file paths, potentially reading sensitive files or overwriting critical data within the restricted `open_basedir` directory. The changed scope (S:C) amplifies impact across the system, leading to high confidentiality, integrity, and availability consequences.
The official GitHub security advisory (GHSA-7922-x7cf-j54x) confirms that EspoCRM version 9.3.4 addresses the issue by fixing the unsanitized handling of `sourceId` in the file path construction. Security practitioners should upgrade to version 9.3.4 or later and review access to formula scripting features for admin users.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-25081
Vulnerability details
EspoCRM is an open source customer relationship management application. Prior to version 9.3.4, EspoCRM's built-in formula scripting engine allowing updating attachment's sourceId thus allowing an authenticated admin to overwrite the `sourceId` field on `Attachment` entities. Because `sourceId` is concatenated directly…
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into a file path with no sanitization in `EspoUploadDir::getFilePath()`, an attacker can redirect any file read or write operation to an arbitrary path within the web server's `open_basedir` scope. Version 9.3.4 fixes the issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Path traversal vuln in web app (T1190) allows unsanitized file read (T1005) and overwrite of critical data (T1565.001) within open_basedir.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates the path traversal by requiring validation and sanitization of the unsanitized `sourceId` input before its use in file path construction.
Enforces least privilege to restrict authenticated administrators from using the formula scripting engine to update sensitive `sourceId` fields unless operationally required.
Restricts `sourceId` inputs to whitelisted values, types, or formats that prevent inclusion of path traversal sequences like '../'.