How severe is CVE-2021-38751?

CVE-2021-38751 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2021-38751 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-38751?

CVE-2021-38751 affects Exponentcms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-38751?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-38751 published?

CVE-2021-38751 was published on 2021-08-16 and last updated on 2026-06-17.

CVE-2021-38751

CVE-2021-38751 is a medium-severity vulnerability in Exponentcms with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-116.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.3
EPSS exploit prediction: 2% (83rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-116
Affected product: Exponentcms
Published: 2021-08-16
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-38751?: 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.
How severe is CVE-2021-38751?: CVE-2021-38751 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2021-38751 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-38751?: CVE-2021-38751 affects Exponentcms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-38751?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-38751 published?: CVE-2021-38751 was published on 2021-08-16 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:a:exponentcms:exponentcms:*:*:*:*:*:*:*:*

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