What’s Vulnerable › Vulnerabilities

CVE-2020-4041: The filename of uploaded files vulnerable to stored XSS in Bolt CMS

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-06-08 · updated 2026-06-17
• Weakness: CWE-79

Description

In Bolt CMS before version 3.7.1, the filename of uploaded files was vulnerable to stored XSS. It is not possible to inject javascript code in the file name when creating/uploading the file. But, once created/uploaded, it can be renamed to inject the payload in it. Additionally, the measures to prevent renaming the file to disallowed filename extensions could be circumvented. This is fixed in Bolt 3.7.1.

Affected products

• bolt: before 3.7.1 — fixed in 3.7.1

How to fix

Upgrade to a fixed version: bolt 3.7.1. Check the vendor advisory for mitigations.

References

• http://packetstormsecurity.com/files/158299/Bolt-CMS-3.7.0-XSS-CSRF-Shell-Upload.html
• http://seclists.org/fulldisclosure/2020/Jul/4
• https://github.com/bolt/bolt/commit/b42cbfcf3e3108c46a80581216ba03ef449e419f
• https://github.com/bolt/bolt/pull/7853
• https://github.com/bolt/bolt/security/advisories/GHSA-68q3-7wjp-7q3j
• http://packetstormsecurity.com/files/158299/Bolt-CMS-3.7.0-XSS-CSRF-Shell-Upload.html
• http://seclists.org/fulldisclosure/2020/Jul/4
• https://github.com/bolt/bolt/commit/b42cbfcf3e3108c46a80581216ba03ef449e419f
• https://github.com/bolt/bolt/pull/7853
• https://github.com/bolt/bolt/security/advisories/GHSA-68q3-7wjp-7q3j

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