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Public proof of concept

CVE-2021-4242

A public proof of concept exists; no exploitation attested.

  • Published2022-11-30
  • WeaknessCWE-707 · CWE-78

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A vulnerability was found in Sapido BR270n, BRC76n, GR297 and RB1732 and classified as critical. Affected by this issue is some unknown functionality of the file ip/syscmd.htm. The manipulation leads to os command injection. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-214592.

Timeline

dates in UTC
  1. 2022-11-3014:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-4242?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-4242?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Sapido br270n firmwareversion to verify
BranchAffectedFixed in
2.1= 2.1.03no fix published
Sapido brc76n firmwareversion to verify
BranchAffectedFixed in
2.1= 2.1.03no fix published
Sapido gr297n firmwareversion to verify
BranchAffectedFixed in
2.1= 2.1.3no fix published

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA4 products

As VulDB, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Sapido BR270n
  • Sapido BRC76n
  • Sapido GR297
  • Sapido RB1732

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2022-11-30

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2025-04-14
  • OpenCVESSVC decisionpoc—
  • CNACVSS 3.16.3known since 2026-10-23
  • NVDCVSS 3.18.8read 2026-10-23
  • CNAweakness (CWE)CWE-707known since 2026-10-23
  • NVDweakness (CWE)CWE-78read 2026-10-23
  • FIRST EPSSEPSS score3.1 %2026-11-03
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2022-11-30
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-2gp5-q39j-fmr2

Frequently asked questions

What is CVE-2021-4242?

A vulnerability was found in Sapido BR270n, BRC76n, GR297 and RB1732 and classified as critical. Affected by this issue is some unknown functionality of the file ip/syscmd.htm. The manipulation leads to os command injection. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-214592.

Is CVE-2021-4242 actively exploited?

A proof-of-concept exploit exists for CVE-2021-4242, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2021-4242?

CVE-2021-4242 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

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Sources for this record