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.
CVSS 6.5EPSS 0.295%Risk 0.67
View source- Published
- 2026-06-25 16:16:36
- Affected versions
- unknown
- Type
- Web application
- Vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N