CVE-2026-23704 File upload in Movable Type (Cloud Edition)
Non-admin users can upload malicious files that execute arbitrary scripts in administrators' browsers, affecting EOL Movable Type versions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-23704?
CVE-2026-23704 is a medium-severity vulnerability in Six Apart Ltd. Movable Type (Cloud Edition), published on 4 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
A non-administrative user can upload malicious files. When an administrator or the product accesses that file, an arbitrary script may be executed on the administrator's browser. Note that Movable Type 7 series and 8.4 series, which are End-of-Life (EOL), are affected by the vulnerability as well.
Weakness: CWE-434
Which versions are affected by CVE-2026-23704?
How do I fix CVE-2026-23704?
No fix has been published for CVE-2026-23704 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-23704 being exploited?
There is no known exploitation of CVE-2026-23704 in the wild and no public exploit code.
Sources
Also known as GHSA-5369-cwvv-7r63.