How severe is CVE-2026-2717?

CVE-2026-2717 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.

Is CVE-2026-2717 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-2717?

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

Does CVE-2026-2717 have an EU (EUVD) identifier?

Yes. CVE-2026-2717 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24637.

When was CVE-2026-2717 published?

CVE-2026-2717 was published on 2026-04-22 and last updated on 2026-06-17.

CVE-2026-2717

CVE-2026-2717 is a medium-severity vulnerability with a CVSS 3.x base score of 5.5. 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-93.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24637
Weakness: CWE-93
Published: 2026-04-22
Last modified: 2026-06-17

Description

The HTTP Headers plugin for WordPress is vulnerable to CRLF Injection in all versions up to, and including, 1.19.2. This is due to insufficient sanitization of custom header name and value fields before writing them to the Apache .htaccess file via `insert_with_markers()`. This makes it possible for authenticated attackers, with Administrator-level access and above, to inject arbitrary newline characters and additional Apache directives into the .htaccess configuration file via the 'Custom Headers' settings, leading to Apache configuration parse errors and potential site-wide denial of service.

Frequently asked questions

What is CVE-2026-2717?: The HTTP Headers plugin for WordPress is vulnerable to CRLF Injection in all versions up to, and including, 1.19.2. This is due to insufficient sanitization of custom header name and value fields before writing them to the Apache .htaccess file via `insert_with_markers()`. This makes it possible for authenticated attackers, with Administrator-level access and above, to inject arbitrary newline characters and additional Apache directives into the .htaccess configuration file via the 'Custom Headers' settings, leading to Apache configuration parse errors and potential site-wide denial of service.
How severe is CVE-2026-2717?: CVE-2026-2717 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.
Is CVE-2026-2717 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-2717?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-2717 have an EU (EUVD) identifier?: Yes. CVE-2026-2717 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24637.
When was CVE-2026-2717 published?: CVE-2026-2717 was published on 2026-04-22 and last updated on 2026-06-17.

References

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