CVE-2026-48944: Joomla Extension - getk2.org - Exposure of sensitive files via attachment copy in K2 extension for Joomla < 2.26

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-25 · updated 2026-10-25
Weakness: CWE-22

Description

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 products

getk2.org K2 extension for Joomla: through 2.26

References

https://www.getk2.org/

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