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Wrc 2533ghbk I FirmwareOperating system · Elecom

CVE-2021-20857

MEDIUM · 5.4 CVSS v3.1 Published 2021-12-01
Fix available
A fix is available. Upgrade to after 1.20 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Cross-site scripting vulnerability in ELECOM LAN router WRC-2533GHBK-I firmware v1.20 and prior allows a remote authenticated attacker to inject an arbitrary script via unspecified vectors.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Cross-site scripting vulnerability in ELECOM LAN router WRC-2533GHBK-I firmware v1.20 and prior allows a remote authenticated attacker to inject arbitrary JavaScript via unspecified vectors. The attacker needs valid credentials to access the router's web interface where the XSS payload gets stored and executed when other authenticated users view the affected page.

MitigationUpdate the router firmware to a version newer than v1.20. Restrict administrative access to trusted IP addresses and ensure strong authentication credentials are in place until the firmware update can be applied.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Wrc 2533ghbk I FirmwareOperating system
Affected:<= 1.20

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm router model
    Access the router's web administration interface (typically via browser at 192.168.0.1 or 192.168.1.1) and check the device information or status page to verify the exact model is WRC-2533GHBK-I
    Affected if The device is an ELECOM WRC-2533GHBK-I router
  2. Check firmware version
    In the router's web interface, locate the firmware version information typically found under Settings, System, or Status pages. Compare your installed version against the affected range (v1.20 and prior)
    Affected if The displayed firmware version is 1.20 or lower
  3. Verify web interface accessibility
    Confirm the router's administrative web interface is accessible from your network. The vulnerability requires the attacker to have valid credentials to log into this interface
    Affected if The web management interface is exposed and uses default or weak credentials
  4. Check for stored XSS indicators
    Review any user-editable fields in the router's web interface (such as network names, hostnames, or custom settings) for any unexpected scripts or unfamiliar saved values that may indicate prior exploitation
    Affected if Unexpected script tags or JavaScript code appear in router configuration fields that you did not intentionally save

You are affected if you have an ELECOM WRC-2533GHBK-I router running firmware version 1.20 or lower, and the router's administrative web interface is accessible with valid credentials.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 1.20
Interim mitigation

Update the router firmware to a version newer than v1.20. Restrict administrative access to trusted IP addresses and ensure strong authentication credentials are in place until the firmware update can be applied.

Recommended fix Moderate confidence

Latest firmware version available from ELECOM for WRC-2533GHBK-I (newer than v1.20)

  1. 1. Visit the official ELECOM support page at www.elecom.co.jp and navigate to the product support section for the WRC-2533GHBK-I router.
  2. 2. Download the latest firmware version available for the WRC-2533GHBK-I router.
  3. 3. Access the router's web administration interface by entering the router's IP address in a web browser.
  4. 4. Log in with administrative credentials.
  5. 5. Locate the firmware upgrade section (typically under 'Management' or 'System' settings).
  6. 6. Upload and apply the downloaded firmware update file.
  7. 7. After the update completes, verify the router has been updated to the latest firmware version.
  8. 8. Confirm the vulnerability is resolved by ensuring the specific XSS vector is no longer exploitable.
Caveat Firmware updates on older routers may occasionally reset configuration settings; backup router configuration before applying update

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Wrc 2533ghbk I Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,150
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,440.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-20857 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data