CVE-2021-20859

CVE-2021-20859 is a high-severity vulnerability in Elecom Wrc-1167gst2 Firmware with a CVSS 3.x base score of 8.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

• Severity: High (CVSS 3.x base score 8.0)
• CVSS v2: 7.7
• EPSS exploit prediction: 1% (42nd percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-78
• Affected product: Elecom Wrc-1167gst2 Firmware
• Published: 2021-12-01
• Last modified: 2026-06-17

Description

ELECOM LAN routers (WRC-1167GST2 firmware v1.25 and prior, WRC-1167GST2A firmware v1.25 and prior, WRC-1167GST2H firmware v1.25 and prior, WRC-2533GS2-B firmware v1.52 and prior, WRC-2533GS2-W firmware v1.52 and prior, WRC-1750GS firmware v1.03 and prior, WRC-1750GSV firmware v2.11 and prior, WRC-1900GST firmware v1.03 and prior, WRC-2533GST firmware v1.03 and prior, WRC-2533GSTA firmware v1.03 and prior, WRC-2533GST2 firmware v1.25 and prior, WRC-2533GST2SP firmware v1.25 and prior, WRC-2533GST2-G firmware v1.25 and prior, and EDWRC-2533GST2 firmware v1.25 and prior) allows a network-adjacent authenticated attacker to execute an arbitrary OS command via unspecified vectors.

Frequently asked questions

What is CVE-2021-20859?

ELECOM LAN routers (WRC-1167GST2 firmware v1.25 and prior, WRC-1167GST2A firmware v1.25 and prior, WRC-1167GST2H firmware v1.25 and prior, WRC-2533GS2-B firmware v1.52 and prior, WRC-2533GS2-W firmware v1.52 and prior, WRC-1750GS firmware v1.03 and prior, WRC-1750GSV firmware v2.11 and prior, WRC-1900GST firmware v1.03 and prior, WRC-2533GST firmware v1.03 and prior, WRC-2533GSTA firmware v1.03 and prior, WRC-2533GST2 firmware v1.25 and prior, WRC-2533GST2SP firmware v1.25 and prior, WRC-2533GST2-G firmware v1.25 and prior, and EDWRC-2533GST2 firmware v1.25 and prior) allows a network-adjacent authenticated attacker to execute an arbitrary OS command via unspecified vectors.

How severe is CVE-2021-20859?

CVE-2021-20859 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-20859 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20859?

CVE-2021-20859 primarily affects Elecom Wrc-1167gst2 Firmware. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20859?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-20859 published?

CVE-2021-20859 was published on 2021-12-01 and last updated on 2026-06-17.

References

• https://jvn.jp/en/jp/JVN88993473/index.html
• https://www.elecom.co.jp/news/security/20211130-01/

Affected products (14)

• cpe:2.3:o:elecom:wrc-1167gst2_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-1167gst2a_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-1167gst2h_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-2533gs2-b_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-2533gs2-w_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-1750gs_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-1750gsv_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-1900gst_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-2533gst_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-2533gst2_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-2533gsta_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-2533gst2sp_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:wrc-2533gst2-g_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:elecom:edwrc-2533gst2_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Elecom Wrc-1167gst2 Firmware

• CVE-2024-23910 — High (CVSS 8.8): Cross-site request forgery (CSRF) vulnerability in ELECOM wireless LAN routers and wireless LAN repeater allows a…
• CVE-2022-25915 — High (CVSS 8.8): Improper access control vulnerability in ELECOM LAN routers (WRC-1167GST2 firmware v1.25 and prior, WRC-1167GST2A…
• CVE-2021-20864 — High (CVSS 8.8): Improper access control vulnerability in ELECOM routers (WRC-1167GST2 firmware v1.25 and prior, WRC-1167GST2A firmware…
• CVE-2021-20861 — High (CVSS 8.8): Improper access control vulnerability in ELECOM LAN routers (WRC-1167GST2 firmware v1.25 and prior, WRC-1167GST2A…
• CVE-2021-20860 — High (CVSS 8.8): Cross-site request forgery (CSRF) vulnerability in ELECOM LAN routers (WRC-1167GST2 firmware v1.25 and prior,…
• CVE-2020-5634 — High (CVSS 8.8): ELECOM LAN routers (WRC-2533GST2 firmware versions prior to v1.14, WRC-1900GST2 firmware versions prior to v1.14,…

All CVEs affecting Elecom Wrc-1167gst2 Firmware →

Other CWE-78 (OS Command Injection) vulnerabilities

• CVE-2026-56004 — Critical (CVSS 10.0): A shellcode injection in the mercurial handler of the obs tar_scm source service before version 0.12.4 could be used by…
• CVE-2026-56415 — Critical (CVSS 10.0): Storage Concentrator (SC & SCVM) contains a command injection vulnerability within the debug.pl script that is…
• CVE-2026-56413 — Critical (CVSS 10.0): Storage Concentrator (SC & SCVM) contains a command injection vulnerability in the ms_service.pl service, which listens…
• CVE-2026-49869 — Critical (CVSS 10.0): Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.45 and 1.3.21, AuthenticationFilter in…
• CVE-2026-49261 — Critical (CVSS 10.0): MariaDB server is a community developed fork of MySQL server. Versions 10.6.1 through 10.6.26, 10.11.1 through…
• CVE-2026-10520 — Critical (CVSS 10.0): An OS Command Injection vulnerability in Ivanti Sentry before the R10.5.2, R10.6.2 and R10.7.1 versions allows a…

Browse all CWE-78 (OS Command Injection) vulnerabilities →