Cyber Resilience

CVE-2021-20853

Medium

Published: 01 December 2021

Published
01 December 2021
Modified
21 November 2024
KEV Added
—
Patch
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CVSS Score v3.1 6.8 CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0035 57.5th percentile
Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-20853 is a medium-severity OS Command Injection (CWE-78) vulnerability in Elecom Wrh-733Gbk Firmware. Its CVSS base score is 6.8 (Medium).

Operationally, ranked in the top 42.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

ELECOM LAN routers (WRH-733GBK firmware v1.02.9 and prior and WRH-733GWH firmware v1.02.9 and prior) allows a network-adjacent attacker with an administrator privilege to execute arbitrary OS commands via unspecified vectors.

CWE(s)
CWE-78

Related Threats

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

Affected Assets

elecom
wrh-733gbk firmware
≤ 1.02.9
elecom
wrh-733gwh firmware
≤ 1.02.9

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.

SC-27 Platform-independent Applications
addresses: CWE-78

Platform-independent apps typically execute inside a managed runtime or sandbox that restricts direct OS command execution, reducing the ability to exploit OS command injection.

SI-10 Information Input Validation
addresses: CWE-78

Validates inputs to block special elements that would alter OS command execution.

References