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CVE-2026-48940LowCVSS 3.4CVE published 25 June 2026Added to mySites.guru 1 January 2026

K2 (com_k2) below 2.26 - CVE-2026-48940 to 48946 - Multiple RCE (unrestricted upload), Path Traversal, Stored XSS, Unauthenticated Folder Delete and Mass Assignment

K2 by JoomlaWorks before 2.26 is affected by a cluster of vulnerabilities disclosed July 2026 and all fixed in 2.26. CVE-2026-48945 and CVE-2026-48946: a privileged K2 author can achieve RCE by uploading a PHP file (via the article attachment path, or a zip/tar extracted under /media/k2/galleries where non-image files keep their extension) and executing it. CVE-2026-48944: path traversal in the attachment copy handler lets an author copy configuration.php or other server files into /media/k2/attachments and download them. CVE-2026-48941: an unauthenticated request to the item.checkin task with a crafted sigProFolder parameter deletes arbitrary folders under /media/k2/galleries. CVE-2026-48940 and CVE-2026-48942: stored XSS via the embedVideo field and the K2 user image field. CVE-2026-48943: mass assignment via plg_user_k2 lets a registered user write arbitrary values to their own #__k2_users row. Update K2 to 2.26 or later.

Is my site affected?

CVE-2026-48940 is checked by 2 rules. Find the extension and release line your site runs:

ExtensionAffected versionsFixed inWhat to do
K2before 2.262.26Update K2 to 2.26 or later.
K2from 1.0 up to and including 2.26after 2.26Update K2 to the newest release from the vendor. This flaw covers versions up to 2.26, so any later release is outside it.
Check whether your sites are affected

How CVE-2026-48940 is scored

The base metrics as CISA-ADP 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.

3.4 Low

CVSS 3.1, scored by CISA-ADP
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:N/A:N

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
PR:H Privileges required
High. Needs an account with elevated rights
UI:R User interaction
Required. Someone has to click or visit something
S:C Scope
Changed. The flaw reaches past the extension it is in

What it does

C:L Confidentiality
Low. Some data can be read
I:N Integrity
None. Nothing can be altered
A:N Availability
None. The site stays up

mySites.guru rates this Critical. Where our assessment and the published record differ, your sites are checked against ours.

Timeline

  1. 1 January 2026mySites.guru check added for K2 (before 2.26)
  2. 25 June 2026CVE-2026-48940 record published by its CNA
  3. 25 June 2026mySites.guru check added for K2 (from 1.0 up to and including 2.26)

Rule details

MediumCVE-2026-48941CVE-2026-48942CVE-2026-48943CVE-2026-48944CVE-2026-48945CVE-2026-48946CVE-2026-489402026-06-25

K2 - K2 (com_k2) 1.0 to 2.26 - Unauthenticated Gallery Folder Deletion, Authenticated Arbitrary File Upload (RCE), Path Traversal and Stored XSS

K2 versions 1.0 to 2.26 are affected by six issues (CVE-2026-48941, CVE-2026-48942, CVE-2026-48943, CVE-2026-48944, CVE-2026-48945, CVE-2026-48946). The most serious needs no login at all: the frontend item.checkin task accepted a sigProFolder parameter and deleted the matching folder under /media/k2/galleries/ with no authentication, no CSRF token and no ownership check, so any anonymous visitor could wipe gallery contents with a single GET request. The other five require author or administrator access that a site administrator has explicitly granted, and are remote code execution via gallery ZIP extraction (non-image files, including .php, were left in place under the publicly served gallery folder), path traversal in the attachment 'existing' field, user property mass-assignment, and stored XSS. Fixed in K2 2.27, released 7 June 2026. K2 2.28 is the current release and also contains the fix. K2 2.26 does NOT contain the fix and is affected. Note that the CVE records contradict themselves on this point: all six are titled 'K2 extension for Joomla < 2.26' while their structured affected range reads 1.0-2.26. The vendor changelog settles it, because 2.26 (31 May 2026) is a YOOtheme Pro and PHP 8 compatibility release while 2.27 is the security release that names every one of these findings.

Affected versions: ≥ 1.0 and ≤ 2.26

Full advisory: github.com · nvd.nist.gov · nvd.nist.gov · nvd.nist.gov · nvd.nist.gov · nvd.nist.gov · nvd.nist.gov

Other vulnerabilities in K2

Updating for CVE-2026-48940 alone can leave a site on a release another rule still matches. These are the other flaws we check for in the same extension.

K2

References

CVE-2026-48940 questions

Which versions are affected by CVE-2026-48940?
CVE-2026-48940 is covered by 2 rules: K2 before 2.26; K2 from 1.0 up to and including 2.26.
How do I fix CVE-2026-48940?
It depends on the extension and release line your site runs. For K2 before 2.26: update K2 to 2.26 or later. For K2 from 1.0 up to and including 2.26: update K2 to the newest release from the vendor. This flaw covers versions up to 2.26, so any later release is outside it.
How severe is CVE-2026-48940?
CISA-ADP scores it 3.4 (Low) under CVSS 3.1. In plain terms: reachable across the internet, needs an account with elevated rights and someone has to click or visit something.

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 15 November 2026.