HOMEVULNERABILITIESCVE-2021-26709
CRITICAL

CVE-2021-26709

CWE-787Published: April 7, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

D-Link DSL-320B-D1 devices through EU_1.25 are prone to multiple Stack-Based Buffer Overflows that allow unauthenticated remote attackers to take over a device via the login.xgi user and pass parameters. NOTE: This vulnerability only affects products that are no longer supported by the maintainer

NVD Source

Technical Analysis

CVE-2021-26709 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

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 9.8.

From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.

CVSS v3.1 Vector Breakdown

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

Affected Vendors & Products

d-link1 product(s)
dsl-320b-d1
Source: NVD CPE · 2 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

ADVISORYhttp://packetstormsecurity.com/files/162133/D-Link-DSL-320B-D1-Pre-Authentication-Buffer-Overflow.html
ADVISORYhttp://seclists.org/fulldisclosure/2021/Apr/15
ADVISORYhttps://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10216
ADVISORYhttps://www.dlink.com/en/security-bulletin
ADVISORYhttp://packetstormsecurity.com/files/162133/D-Link-DSL-320B-D1-Pre-Authentication-Buffer-Overflow.html
ADVISORYhttp://seclists.org/fulldisclosure/2021/Apr/15
ADVISORYhttps://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10216
ADVISORYhttps://www.dlink.com/en/security-bulletin

All References (8)

→
http://packetstormsecurity.com/files/162133/D-Link-DSL-320B-D1-Pre-Authentication-Buffer-Overflow.htmlExploit · Third Party Advisory · VDB Entry
→
http://seclists.org/fulldisclosure/2021/Apr/15Mailing List · Third Party Advisory
→
https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10216Vendor Advisory
→
https://www.dlink.com/en/security-bulletinVendor Advisory
→
http://packetstormsecurity.com/files/162133/D-Link-DSL-320B-D1-Pre-Authentication-Buffer-Overflow.htmlExploit · Third Party Advisory · VDB Entry
→
http://seclists.org/fulldisclosure/2021/Apr/15Mailing List · Third Party Advisory
→
https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10216Vendor Advisory
→
https://www.dlink.com/en/security-bulletinVendor Advisory

Quick Facts

CVE IDCVE-2021-26709
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-787
CISA KEVNo
Affected1 vendor(s)
PublishedApr 7, 2021

Related CVEs (CWE-787)

CVE-2013-5610
10.0
CVE-2012-3957
10.0
CVE-2012-0751
10.0
CVE-2011-1807
10.0
CVE-2004-0978
10.0
CVE-2014-1478
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-26709 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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