CVE-2021-38751
A HTTP Host header attack exists in ExponentCMS 2.6 and below in /exponent_constants.php. A...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-38751- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-116
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-38751- Updated
- 2026-11-02
EUVDEUVD-2021-25188 No score
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.
- Record
EUVD-2021-25188- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-mg75-hvvv-r45q No score
A HTTP Host header attack exists in ExponentCMS 2.6 and below in /exponent_constants.php. A...
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.
- Record
GHSA-mg75-hvvv-r45q- Weakness
- CWE-116
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-38751- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
Affected products
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Nuclei | ExponentCMS <= 2.6 - Host Header Injection |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, Nuclei, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-38751 is a medium vulnerability (CVSS 4.3) in Exponentcms, published August 16, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.47%, the 84th percentile. No source names a fixed version.