CVE-2020-9277Public exploitNetwork attack vector

Unauthenticated device takeover via CGI path confusion

Published Apr 20, 2020 · Updated Aug 4, 2024

Authentication bypass in D-Link DSL-2640B B2 EU_4.01B allows remote attackers to perform administrative tasks through crafted CGI URLs. The web server exempts paths beginning with /images/ from authentication, while do_cgi() locates a CGI module anywhere in the URL. Access to the device's LAN interface, or browser pivoting from a visited malicious site, is required; successful requests can change the administrator password and grant full device control.

CVSS severity9.8
Critical
EPSS probability2.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in D-Link DSL-2640B B2 EU_4.01B allows remote attackers to perform administrative tasks through crafted CGI URLs. The web server exempts paths beginning with /images/ from authentication, while do_cgi() locates a CGI module anywhere in the URL. Access to the device's LAN interface, or browser pivoting from a visited malicious site, is required; successful requests can change the administrator password and grant full device control.

The record

CVE
CVE-2020-9277
Published
Apr 20, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 20, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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