CVE-2026-33656: EspoCRM vulnerable to authenticated RCE via Formula with path traversal in attachment `sourceId`, exploitable by admin user

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-22 · updated 2026-06-17
Weakness: CWE-22

Description

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 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.

Affected products

espocrm: before 9.3.4 — fixed in 9.3.4

How to fix

Upgrade to a fixed version: espocrm 9.3.4. Check the vendor advisory for mitigations.

References

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