Security readout for executives and security teams
Plain-English summary
Movable Type has a cross-site scripting flaw in its List of Assets screen. A remote attacker could inject script or HTML, which may affect users who view the vulnerable screen. Public sources do not provide CVSS details or attack-vector specifics, so business urgency depends on whether affected Movable Type admin interfaces are in use.
Executive priority
Treat this as a moderate-priority remediation item for any active Movable Type deployment, especially systems used by administrators. Absence of CVSS and exploitation evidence lowers urgency, but XSS in management workflows can still create account and content integrity risk.
Technical view
CVE-2021-20811 is an XSS vulnerability affecting Movable Type 7 r.4903 and earlier, 6.8.0 and earlier, Movable Type Advanced, Movable Type Premium, and Premium Advanced versions listed by JVN/CVE. The injection vector is unspecified in the provided sources, and no CWE or CVSS data is supplied.
Likely exposure
Exposure is likely limited to organizations running the listed Movable Type products and versions. Risk is higher where administrative or asset-management workflows are internet-accessible or used by privileged staff.
Exploitation context
The source bundle does not show CISA KEV listing, active exploitation, public exploit code, or detailed exploit mechanics. It only states that remote attackers can inject arbitrary script or HTML through unspecified vectors.
Researcher notes
The provided record lacks CVSS, CWE, proof-of-concept details, and named input vectors. Validation should focus on version confirmation and vendor advisory mapping rather than exploit reproduction. Do not assume affected components beyond the listed Movable Type products.
Mitigation direction
- Identify all Movable Type and Movable Type Advanced/Premium instances.
- Upgrade according to the Movable Type and JVN advisories.
- Restrict access to Movable Type administrative interfaces where feasible.
- Review vendor guidance before applying compensating controls.
Validation and detection
- Inventory deployed Movable Type product names and exact versions.
- Confirm whether versions match the affected ranges listed by CVE/JVN.
- Check whether the List of Assets screen is reachable by untrusted users.
- Verify upgrade status against vendor release guidance.
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-2021-20811 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.