Cyber Resilience

CVE-2021-20810

Medium

Published: 26 August 2021

Published
26 August 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS Score 0.0033 56.5th percentile
Risk Priority 12 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-20810 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Sixapart Movable Type. Its CVSS base score is 6.1 (Medium).

Operationally, ranked in the top 43.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Cross-site scripting vulnerability in Website Management 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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

sixapart
movable type
≤ 1.44 · ≤ 1.44 · 6.0 — 6.8.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

References