CVE-2017-16798 — In CMS Made Simple 2

In CMS Made Simple 2.2.3.1, the is_file_acceptable function in modules/FileManager/action.upload.php only blocks file extensions that begin or end with a "php" substring, which allows remote attackers to bypass intended access restrictions or trigger XSS via other exten

01What is this vulnerability?

In CMS Made Simple 2.2.3.1, the is_file_acceptable function in modules/FileManager/action.upload.php only blocks file extensions that begin or end with a "php" substring, which allows remote attackers to bypass intended access restrictions or trigger XSS via other extensions, as demonstrated by .phtml, .pht, .html, or .svg.

02Affected products

No structured affected-product list available — see references below for vendor advisories.

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2017-11-12T18:29:00.300
• Last modified: 2026-05-13T00:24:29.033

09References

• github.com — https://github.com/bsmali4/cve/blob/master/CMS%20Made%20Simple%20UPLOAD%20FILE%2…
• github.com — https://github.com/bsmali4/cve/blob/master/CMS%20Made%20Simple%20UPLOAD%20FILE%2…