Security readout for executives and security teams
Plain-English summary
CVE-2021-20814 is a cross-site scripting issue in the ContentType Information Widget Plugin settings screen for certain Movable Type products. An attacker could inject script or HTML through unspecified inputs. The sources do not provide CVSS, exploit details, or evidence of active exploitation.
Executive priority
Treat this as a targeted web-application risk, not a confirmed emergency. Prioritize remediation for public or partner-accessible Movable Type administration environments, especially where privileged users could be exposed to injected script in settings screens.
Technical view
The vulnerability affects Movable Type 7 r.4903 and earlier, Movable Type Advanced 7 r.4903 and earlier, and Movable Type Premium 1.44 and earlier. The flaw is XSS in the plugin settings screen. Public sources do not specify the exact vector, privilege requirement, or fixed version details in the provided bundle.
Likely exposure
Exposure is most likely in organizations running the listed Movable Type versions with the ContentType Information Widget Plugin enabled or accessible. Internet-facing administration or settings access would raise concern, but the source bundle does not confirm required authentication.
Exploitation context
The CVE says remote attackers can inject arbitrary script or HTML via unspecified vectors. It is not listed as CISA KEV in the provided bundle, and no cited source states active exploitation. Practical exploitability cannot be confirmed from the available evidence.
Researcher notes
The source bundle lacks CVSS, CWE, authentication context, affected component internals, and exact input vectors. Avoid assuming stored versus reflected XSS, exploit maturity, or specific fixes beyond vendor/JVN guidance. Validation should focus on version exposure and plugin presence.
Mitigation direction
- Review Movable Type and JVN guidance for the supported update path.
- Move affected Movable Type installations beyond the listed vulnerable versions.
- Restrict access to Movable Type administrative and settings screens.
- Disable or remove the affected plugin if vendor guidance supports doing so.
Validation and detection
- Inventory Movable Type, Movable Type Advanced, and Movable Type Premium versions.
- Check whether the ContentType Information Widget Plugin is installed or enabled.
- Confirm whether settings screens are exposed to untrusted users or networks.
- Review application logs for suspicious script or HTML submitted to settings workflows.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-20814 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://movabletype.org/news/2021/08/mt-780-681-released.htmlCVE reference · x_refsource_MISC
- https://jvn.jp/en/jp/JVN97545738/index.htmlCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.