CVE-2026-48944: The K2 frontend article-save handler accepts an `attachment[N][existing]` POST field that is concatenated with `JPATH_SITE/` and passed to `JFile::copy()`…

PriorityP340medium6.5CVSS 3.1

AVNACLPRLUINSUCHINAN

EPSS

0.29%

21.2th percentile

The K2 frontend article-save handler accepts an `attachment[N][existing]` POST field that is concatenated with `JPATH_SITE/` and passed to `JFile::copy()`. `JPath::clean` does NOT strip `..`, and there is no allow-list of source paths. An Author can therefore copy `configuration.php` (or any other file readable by the web user — including `../../../etc/passwd`) into `/media/k2/attachments/`, then retrieve the contents via the K2 attachment-download endpoint.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
getk2.org	k2_extension_for_joomla	—	—
joomlaworks	k2	<= 2.26	—

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