Skip to main content
mySites.guru
Free Audit
J!Awards 2026mySites.guru is shortlisted for Your Favourite Tool in Your Joomla WorkflowVote by 11 OctoberHow to vote
CVE-2026-57827CriticalCVSS 10.0CVE published 11 July 2026Added to mySites.guru 10 July 2026

RSFiles! (com_rsfiles) <= 1.17.11 - Unauthenticated Arbitrary File Upload (RCE)

RSFiles! (com_rsfiles) version 1.17.11 and earlier contain an arbitrary file upload flaw in the front-end upload handler that leads to remote code execution. The file-type allow-list and the upload permission check run in a separate pre-flight step, while the method that actually writes the file trusts an attacker-supplied filename and never re-validates the extension, so a .php web shell can be written into the web-served download folder and executed. On builds up to 1.17.11 this is exploitable without any authentication. RSJoomla released a patched build on 2026-07-10 that is STILL numbered 1.17.11 (the version string was not bumped); it only closes the unauthenticated path. A residual bypass remains that lets any user permitted to upload (and any anonymous visitor on sites that allow public uploads) still write an executable .php. Because the version number is unchanged, every install reporting 1.17.11 or lower must be treated as affected. No fixed version is available yet - the issue has been reported to the vendor and a follow-up release is awaited. Mitigation until then: restrict RSFiles uploads to trusted user groups only, or disable uploads entirely (set Enable Upload to No), or turn on the extension's Secure Download Folder option so a .htaccess disables PHP execution in the download folder. Also covered by this rule: CVE-2025-50057, an unauthenticated denial of service via the RSFiles! search feature in 1.16.3 to 1.17.7.

Is my site affected?

Affected
RSFiles! up to and including 1.17.11
Fixed in
A release after 1.17.11
What to do
Update RSFiles! to the newest release from the vendor. This flaw covers versions up to 1.17.11, so any later release is outside it.
Check whether your sites are affected

How CVE-2026-57827 is scored

The base metrics as Joomla CNA published them, and what each one means for a site running an affected version. Threat and environmental metrics are left out: they describe a moment or a particular install rather than the flaw.

10.0 Critical

CVSS 4.0, scored by Joomla CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/U:Red

How it is reached

AV:N Attack vector
Network. Reachable across the internet
AC:L Attack complexity
Low. Nothing to work around, it just works
AT:N Attack requirements
None. Works against any affected install
PR:N Privileges required
None. No account needed
UI:N User interaction
None. Nobody has to be tricked into anything

What it does to the site

VC:H Confidentiality
High. Everything the site holds can be read
VI:H Integrity
High. Data and files can be altered at will
VA:H Availability
High. The site can be taken down

What it does beyond the site

SC:H Confidentiality
High. Data on other systems can be read
SI:H Integrity
High. Other systems can be altered
SA:H Availability
High. Other systems can be taken down

Timeline

  1. 10 July 2026mySites.guru check added for RSFiles! (up to and including 1.17.11)
  2. 11 July 2026CVE-2026-57827 record published by its CNA

Rule details

Other vulnerabilities in RSFiles!

Updating for CVE-2026-57827 alone can leave a site on a release another rule still matches. These are the other flaws we check for in the same extension.

RSFiles!

References

CVE-2026-57827 questions

Which versions are affected by CVE-2026-57827?
CVE-2026-57827 affects RSFiles! up to and including 1.17.11.
How do I fix CVE-2026-57827?
Update RSFiles! to the newest release from the vendor. This flaw covers versions up to 1.17.11, so any later release is outside it.
How severe is CVE-2026-57827?
Joomla CNA scores it 10.0 (Critical) under CVSS 4.0. In plain terms: reachable across the internet, no account needed and nobody has to be tricked into anything.

Running an affected version on a site you manage?

A free audit tells you which of your Joomla and WordPress sites run an affected version, which are out of date, and which have not been backed up. No card required. If a site is already compromised, fix.mysites.guru is a single fixed fee per incident, usually resolved the same day.

This check is part of the mySites.guru Joomla vulnerability scanner, which reads every installed extension's version on each audit. Browse the rest of the Joomla vulnerability database.

Rules current as of 5 October 2026.