How severe is CVE-2017-16941?

CVE-2017-16941 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-16941 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-16941?

CVE-2017-16941 affects Octobercms October. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-16941?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2017-16941 published?

CVE-2017-16941 was published on 2017-11-25 and last updated on 2026-06-17.

CVE-2017-16941

CVE-2017-16941 is a high-severity vulnerability in Octobercms October with a CVSS 3.x base score of 8.8. 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-434.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.5
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-434
Affected product: Octobercms October
Published: 2017-11-25
Last modified: 2026-06-17

Description

October CMS through 1.0.428 does not prevent use of .htaccess in themes, which allows remote authenticated users to execute arbitrary PHP code by downloading a theme ZIP archive from /backend/cms/themes, and then uploading and importing a modified archive with two new files: a .php file and a .htaccess file. NOTE: the vendor says "I don't think [an attacker able to login to the system under an account that has access to manage/upload themes] is a threat model that we need to be considering.

Frequently asked questions

What is CVE-2017-16941?: October CMS through 1.0.428 does not prevent use of .htaccess in themes, which allows remote authenticated users to execute arbitrary PHP code by downloading a theme ZIP archive from /backend/cms/themes, and then uploading and importing a modified archive with two new files: a .php file and a .htaccess file. NOTE: the vendor says "I don't think [an attacker able to login to the system under an account that has access to manage/upload themes] is a threat model that we need to be considering.
How severe is CVE-2017-16941?: CVE-2017-16941 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-16941 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-16941?: CVE-2017-16941 affects Octobercms October. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-16941?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2017-16941 published?: CVE-2017-16941 was published on 2017-11-25 and last updated on 2026-06-17.

References

https://github.com/octobercms/october/issues/3257

Affected products (1)

cpe:2.3:a:octobercms:october:*:*:*:*:*:*:*:*

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