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CVE-2026-117543HighCVSS 8.9CVE published 12 November 2026Added to mySites.guru 12 November 2026

jDownloads (com_jdownloads) below 4.1.8 - RCE via Frontend Thumbnail Upload, Restricted File Download (IDOR), SSRF, Path Traversal and Unauthenticated Scan Key Disclosure

jDownloads 4.1.8 (12 November 2026) is a security release fixing nine issues reported by Lukasz Rybak and Fadilulah Ajeigbe and coordinated by the Joomla Security Strike Team. The Joomla CNA published five CVEs the same day, each stating jDownloads 1.0.0 to 4.1.7 as affected: CVE-2026-117551 (CVSS 4.0 10.0 Critical): insufficient validation of frontend thumbnail uploads let users with upload permission place executable files on the server, giving PHP code execution. CVE-2026-117543 (8.9 High): HTTP redirects when fetching external download URLs bypassed destination validation, allowing server-side requests to internal hosts and disclosure of the responses (SSRF). CVE-2026-117544 (8.2 High): the other_file_id parameter delivered another download's file without enforcing that download's access restrictions. CVE-2026-117550 (7.1 High): manipulated frontend submission values published submissions despite auto-publish being off and assigned ownership against policy. CVE-2026-117542 (5.1 Medium): a manipulated update_file parameter moved files from outside the permitted server-file folder into a download. Without a CVE so far: in 4.1.7 administrator/components/com_jdownloads/helpers/scan-interface.php opens without a login and prints the scan secret key, which is all the URL-based scan (scan.php) checks before creating, unpublishing or deleting download records (4.0.52 has no scan-interface.php). 4.1.8 for Joomla 5 and 6 is the only fixed release; no 4.0.x or 3.9.x fix has been published, so sites on older lines must move to 4.1.8 (4.0.x via 4.0.52). After updating, rotate the scan secret key in the jDownloads options and update any scheduled URL-based scan jobs, because the update does not rotate an existing key.

Is my site affected?

Affected
jDownloads before 4.1.8
Fixed in
4.1.8
What to do
Update jDownloads to 4.1.8 or later.
Check whether your sites are affected

How CVE-2026-117543 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.

8.9 High

CVSS 4.0, scored by Joomla CNA
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

How it is reached

AV:N Attack vector
Network. Reachable across the internet
AC:H Attack complexity
High. The attacker has to defeat a mitigation first
AT:P Attack requirements
Present. Needs a particular deployment or race to line up
PR:H Privileges required
High. Needs an account with elevated rights
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

The rule below is rated Critical for the set of 5 CVEs it covers together, not for this record on its own.

Timeline

  1. 12 November 2026CVE-2026-117543 record published by its CNA
  2. 12 November 2026mySites.guru check added for jDownloads (before 4.1.8)
  3. 12 November 2026We published: jDownloads 4.1.8 Fixes a Critical File Upload RCE and Eight More Security Issues

Rule details

Our disclosure post

jDownloads 4.1.8 Fixes a Critical File Upload RCE and Eight More Security Issues

jDownloads 4.1.8 Fixes a Critical File Upload RCE and Eight More Security Issues

jDownloads 4.1.8 fixes five CVEs in the Joomla extension, led by a 10.0 Critical file upload flaw that runs PHP code. Every earlier version is affected.

Other vulnerabilities in jDownloads

Updating for CVE-2026-117543 alone can leave a site on a release another rule still matches. These are the other flaws we check for in the same extension.

jDownloads

Latest safe version: 4.1.8

References

CVE-2026-117543 questions

Which versions are affected by CVE-2026-117543?
CVE-2026-117543 affects jDownloads before 4.1.8. The fix is in 4.1.8.
How do I fix CVE-2026-117543?
Update jDownloads to 4.1.8 or later. Then confirm the installed version on the Joomla administrator's Extensions: Manage screen.
How severe is CVE-2026-117543?
Joomla CNA scores it 8.9 (High) under CVSS 4.0. In plain terms: reachable across the internet, needs an account with elevated rights and nobody has to be tricked into anything.

Running an affected version on a site you manage?

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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 12 November 2026.