HOMEVULNERABILITIESCVE-2021-4242
HIGH

CVE-2021-4242

CWE-707Published: November 30, 2022· Updated: Jun 17, 2026

8.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-4242 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

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 VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

sapido8 product(s)
br270n firmwarebr270nbrc76n firmwarebrc76ngr297n firmwaregr297nrb-1732 firmwarerb-1732
Source: NVD CPE · 8 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://blog.csdn.net/qq_44159028/article/details/114590267
ADVISORYhttps://github.com/smallpiggy/Sapido--rce/blob/main/Sapido%E8%B7%AF%E7%94%B1%E5%99%A8-rce.py
ADVISORYhttps://vuldb.com/?id.214592
ADVISORYhttps://blog.csdn.net/qq_44159028/article/details/114590267
ADVISORYhttps://github.com/smallpiggy/Sapido--rce/blob/main/Sapido%E8%B7%AF%E7%94%B1%E5%99%A8-rce.py
ADVISORYhttps://vuldb.com/?id.214592

All References (6)

→
https://blog.csdn.net/qq_44159028/article/details/114590267Exploit · Third Party Advisory
→
https://github.com/smallpiggy/Sapido--rce/blob/main/Sapido%E8%B7%AF%E7%94%B1%E5%99%A8-rce.pyExploit · Third Party Advisory
→
https://vuldb.com/?id.214592Third Party Advisory
→
https://blog.csdn.net/qq_44159028/article/details/114590267Exploit · Third Party Advisory
→
https://github.com/smallpiggy/Sapido--rce/blob/main/Sapido%E8%B7%AF%E7%94%B1%E5%99%A8-rce.pyExploit · Third Party Advisory
→
https://vuldb.com/?id.214592Third Party Advisory

Quick Facts

CVE IDCVE-2021-4242
CVSS Score8.8 / 10
SeverityHIGH
WeaknessCWE-707
CISA KEVNo
Affected1 vendor(s)
PublishedNov 30, 2022

Related CVEs (CWE-707)

CVE-2022-4011
9.8
CVE-2022-4088
9.8
CVE-2022-4051
9.8
CVE-2022-4012
9.8
CVE-2022-4015
9.8
CVE-2022-4375
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-4242 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.COM. CVE data is provided under the NVD usage policy.
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