CVE-2021-38751

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-08-16 · updated 2026-06-17
Weakness: CWE-116

Description

A HTTP Host header attack exists in ExponentCMS 2.6 and below in /exponent_constants.php. A modified HTTP header can change links on the webpage to an arbitrary value, leading to a possible attack vector for MITM.

Affected products

Exponentcms: before 2.6 — fixed in 2.6

How to fix

Upgrade to a fixed version: Exponentcms 2.6. Check the vendor advisory for mitigations.

References

https://github.com/exponentcms/exponent-cms/issues/1544
https://github.com/exponentcms/exponent-cms/issues/1544

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