CVE-2026-33741: EspoCRM: Stored XSS via SVG attachment loading same-origin JavaScript
EspoCRM is an open source customer relationship management application. Versions 9.3.3 and below allow authenticated users to upload SVG attachments through normal attachment-capable fields and later serve those SVG files as top-level inline documents through both the attachment and image entry points, resulting in stored cross-user XSS reachable through a normal attachment workflow. Although inline SVG script is blocked by the response CSP, the same CSP still allows same-origin external script. As a result, an attacker can upload a malicious SVG together with a second attacker-controlled JavaScript attachment, then trick another user into opening the SVG to execute JavaScript in the victim's EspoCRM origin. This issue has been fixed in version 9.3.4.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
EspoCRMto a version that resolves this vulnerability.Fixed in 9.3.4 - Compensating control
Restrict who can upload SVG attachments via attachment-capable fields until EspoCRM is upgraded to 9.3.4, since versions 9.3.3 and below allow authenticated users to upload SVGs that can execute stored cross-user XSS when served as top-level inline documents.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33741?
CVE-2026-33741 has a severity rating that depends on the potential impact of stored XSS attacks in EspoCRM.
How do I fix CVE-2026-33741?
To fix CVE-2026-33741, upgrade EspoCRM to a version above 9.3.3 that mitigates the stored XSS vulnerability.
What versions of EspoCRM are affected by CVE-2026-33741?
EspoCRM versions 9.3.3 and below are affected by CVE-2026-33741.
What type of vulnerability is CVE-2026-33741?
CVE-2026-33741 is classified as a stored cross-site scripting (XSS) vulnerability.
Who is affected by CVE-2026-33741?
Authenticated users of EspoCRM are affected by CVE-2026-33741 due to the ability to upload malicious SVG attachments.