XSS in Sixapart Movable Type
CVE-2021-20811
Cross-site scripting vulnerability in List of Assets screen of Movable Type (Movable Type 7 r.4903 and earlier (Movable Type 7 Series), Movable Type 6.8.0 and earlier (Movable Type 6 Series), Movable Type Advanced 7 r.4903 and earlier (Movable Type Advanced 7 Series), Movable Type Premium 1.44 and earlier, and Movable Type Premium Advanced 1.44 and earlier) allows remote attackers to inject arbitrary script or HTML via unspecified vectors.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.009 (58.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 58.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000
Affected products
- Sixapart Movable Type
- Six Apart Ltd. Movable Type — versions Movable Type 7 r.4903 and earlier (Movable Type 7 Series), Movable Type 6.8.0 and earlier (Movable Type 6 Series), Movable Type Advanced 7 r.4903 and earlier (Movable Type Advanced 7 Series), Movable Type Premium 1.44 and earlier, and Movable Type Premium Advanced 1.44 and earlier
Weakness classification (CWE)
Public proof-of-concept exploits
References
- movabletype.org/news/2021/08/mt-780-681-released.html (Release Notes, Vendor Advisory)
- jvn.jp/en/jp/JVN97545738/index.html (Third Party Advisory)
Frequently asked questions
- What is CVE-2021-20811?
- CVE-2021-20811 is a medium-severity vulnerability in Sixapart Movable Type, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-08-26.
- How severe is CVE-2021-20811?
- Medium severity. CVSS v3 base score is 6.1 out of 10.
- Is CVE-2021-20811 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.