CVE-2021-39136: Cross-site scripting vulnerability in file upload

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-08-25 · updated 2026-06-17
Weakness: CWE-79

Description

baserCMS is an open source content management system with a focus on Japanese language support. In affected versions there is a cross-site scripting vulnerability in the file upload function of the management system of baserCMS. Users are advised to update as soon as possible. No workaround are available to mitigate this issue.

Affected products

baserproject basercms: before 4.5.1 — fixed in 4.5.1

How to fix

Upgrade to a fixed version: baserproject basercms 4.5.1. Check the vendor advisory for mitigations.

References

http://jvn.jp/en/jp/JVN14134801/index.html
https://basercms.net/security/JVN_14134801
https://github.com/baserproject/basercms/commit/568d4cab5ba1cdee7bbf0133c676d02a98f6d7bc
https://github.com/baserproject/basercms/security/advisories/GHSA-hgjr-632x-qpp3
http://jvn.jp/en/jp/JVN14134801/index.html
https://basercms.net/security/JVN_14134801
https://github.com/baserproject/basercms/commit/568d4cab5ba1cdee7bbf0133c676d02a98f6d7bc
https://github.com/baserproject/basercms/security/advisories/GHSA-hgjr-632x-qpp3

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