CVE-2021-20837
CriticalExploitedPublic exploitMovable Type 7 r.5002 and earlier (Movable Type 7 Series), Movable Type 6.8.2 and earlier (Movable Type 6 Series), Movable Type Advanced 7 r.5002 and earlier (Movable Type Advanced 7 Series), Movable Type Advanced 6.8.2 and earlier (Movable Type Advanced 6 Series), Movable Type…
Published Oct 26, 2021 · Updated Nov 21, 2024
Key Facts
Patch immediately- CVE-2021-20837 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Movable Type (Sixapart).
- It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since May 31, 2022. Public exploit code is available.
- EPSS estimates a 88% probability of exploitation in the next 30 days.
- Fixed versions are available, including Movable Type <=1.46, Movable Type <=6.3.11, Movable Type <=6.8.2.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
88%
Higher than 99.7% of all scored CVEs
Exploited in the wild
Yes
2 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-20837 brief as a PDF
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Description
Movable Type 7 r.5002 and earlier (Movable Type 7 Series), Movable Type 6.8.2 and earlier (Movable Type 6 Series), Movable Type Advanced 7 r.5002 and earlier (Movable Type Advanced 7 Series), Movable Type Advanced 6.8.2 and earlier (Movable Type Advanced 6 Series), Movable Type Premium 1.46 and earlier, and Movable Type Premium Advanced 1.46 and earlier allow remote attackers to execute arbitrary OS commands via unspecified vectors. Note that all versions of Movable Type 4.0 or later including unsupported (End-of-Life, EOL) versions are also affected by this vulnerability.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | May 31, 2022 | n/a | Not reported |
| CIRCL KEV | Oct 14, 2023 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
6 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Movable TypeSixapart | >= Movable Type 7 r.5002 and earlier (Movable Type 7 Series), Movable Type 6.8.2 and earlier (Movable Type 6 Series), Movable Type Advanced 7 r.5002 and earlier (Movable Type Advanced 7 Series), Movable Type Advanced 6.8.2 and earlier (Movable Type Advanced 6 Series), Movable Type Premium 1.46 and earlier, and Movable Type Premium Advanced 1.46 and earlier | 6.3.11 |
Patched Releases
Movable Type
<=1.46, <=6.3.11, <=6.8.2
Timeline
Publicly disclosed
Oct 26, 2021
Added to Industry KEV feed
May 31, 2022
Added to CIRCL KEV
Oct 14, 2023
Last updated
Nov 21, 2024
Weakness Type
- CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
References
- advisoryhttp://packetstormsecurity.com/files/164818/Movable-Type-7-r.5002-XMLRPC-API-Remote-Command-Injection.html
- advisoryhttps://jvn.jp/en/jp/JVN41119755/index.html
- advisoryhttps://movabletype.org/news/2021/10/mt-782-683-released.html
- exploithttp://packetstormsecurity.com/files/164705/Movable-Type-7-r.5002-XMLRPC-API-Remote-Command-Injection.html
- exploitVulnCheck exploitation report
FAQ
Common Questions.
Movable Type 7 r.5002 and earlier (Movable Type 7 Series), Movable Type 6.8.2 and earlier (Movable Type 6 Series), Movable Type Advanced 7 r.5002 and earlier (Movable Type Advanced 7 Series), Movable Type Advanced 6.8.2 and earlier (Movable Type Advanced 6 Series), Movable Type Premium 1.46 and earlier, and Movable Ty…
Affected: Movable Type (Sixapart) versions >= Movable Type 7 r.5002 and earlier (Movable Type 7 Series), Movable Type 6.8.2 and earlier (Movable Type 6 Series), Movable Type Advanced 7 r.5002 and earlier (Movable Type Advanced 7 Series), Movable Type Advanced 6.8.2 and earlier (Movable Type Advanced 6 Series), Movable Type Premium 1.46 and earlier, and Movable Type Premium Advanced 1.46 and earlier. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since May 31, 2022.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Movable Type <=1.46, Movable Type <=6.3.11, Movable Type <=6.8.2.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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