HOMEVULNERABILITIESCVE-2021-20861
HIGH

CVE-2021-20861

NVD-CWE-OtherPublished: December 1, 2021· Updated: Jun 17, 2026

8.8
CVSS v3.1

Official Description

Improper access control vulnerability in 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 bypass access restriction and to access the management screen of the product via unspecified vectors.

NVD Source

Technical Analysis

CVE-2021-20861 requires adjacent network access, limiting remote exploitation but still posing risk in shared or local network environments.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorAdjacent
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

elecom28 product(s)
wrc-1167gst2 firmwarewrc-1167gst2wrc-1167gst2a firmwarewrc-1167gst2awrc-1167gst2h firmwarewrc-1167gst2hwrc-2533gs2-b firmwarewrc-2533gs2-bwrc-2533gs2-w firmwarewrc-2533gs2-wwrc-1750gs firmwarewrc-1750gs+16
Source: NVD CPE · 28 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

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

All References (4)

→
https://jvn.jp/en/jp/JVN88993473/index.htmlThird Party Advisory
→
https://www.elecom.co.jp/news/security/20211130-01/Vendor Advisory
→
https://jvn.jp/en/jp/JVN88993473/index.htmlThird Party Advisory
→
https://www.elecom.co.jp/news/security/20211130-01/Vendor Advisory

Quick Facts

CVE IDCVE-2021-20861
CVSS Score8.8 / 10
SeverityHIGH
WeaknessNVD-CWE-Other
CISA KEVNo
Affected1 vendor(s)
PublishedDec 1, 2021

Related CVEs (NVD-CWE-Other)

CVE-2000-0587
10.0
CVE-2000-0585
10.0
CVE-2000-0514
10.0
CVE-2000-0525
10.0
CVE-2005-4090
10.0
CVE-2000-0614
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-20861 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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