Description
ExpressionEngine before 5.3.2 allows remote attackers to upload and execute arbitrary code in a .php%20 file via Compose Msg, Add attachment, and Save As Draft actions. A user with low privileges (member) is able to upload this. It is possible to bypass the MIME type check and file-extension check while uploading new files. Short aliases are not used for an attachment; instead, direct access is allowed to the uploaded files. It is possible to upload PHP only if one has member access, or registration/forum is enabled and one can create a member with the default group id of 5. To exploit this, one must to be able to send and compose messages (at least).
References (2)
Core 2
Core References
Vendor Advisory x_refsource_misc
https://expressionengine.com/blog
Exploit, Third Party Advisory x_refsource_misc
https://gist.github.com/mariuszpoplwski/51604d8a6d7d78fffdf590c25e844e09
Scores
CVSS v3
8.8
EPSS
0.0112
EPSS Percentile
78.3%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Details
CWE
CWE-434
Status
published
Products (1)
expressionengine/expressionengine
< 5.3.2
Published
Jun 24, 2020
Tracked Since
Feb 18, 2026