Skip to main content
Public proof of conceptFix available

CVE-2020-27866

A public proof of concept exists; no exploitation attested.

  • Published2021-02-12
  • Fixed in1.2.0.76
  • WeaknessCWE-287 · CWE-288

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

This vulnerability allows network-adjacent attackers to bypass authentication on affected installations of NETGEAR R6020, R6080, R6120, R6220, R6260, R6700v2, R6800, R6900v2, R7450, JNR3210, WNR2020, Nighthawk AC2100, and Nighthawk AC2400 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the mini_httpd service, which listens on TCP port 80 by default. The issue results from incorrect string matching logic when accessing protected pages. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of root. Was ZDI-CAN-11355.

Timeline

dates in UTC
  1. 2021-02-1200:15CVE 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-2020-27866?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-27866?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Netgear ac2100 firmwareversion to verify
BranchAffectedFixed in
1.2< 1.2.0.761.2.0.76
Netgear ac2400 firmwareversion to verify
BranchAffectedFixed in
1.2< 1.2.0.761.2.0.76
Netgear ac2600 firmwareversion to verify
BranchAffectedFixed in
1.2< 1.2.0.761.2.0.76

16 more products in the sources.

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

Fix

  1. Update Netgear ac2100 firmware to 1.2.0.76

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
available
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.18.8read 2026-10-23
  • CNACVSS 3.08.8known since 2026-10-23
  • NVDCVSS 2.08.3read 2026-10-23
  • CNAweakness (CWE)CWE-288known since 2026-10-23
  • NVDweakness (CWE)CWE-287read 2026-10-23
  • FIRST EPSSEPSS score8.7 %2026-11-03
  • ProjectDiscoverydetectionread 2026-11-03

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-02-12
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-27866?

This vulnerability allows network-adjacent attackers to bypass authentication on affected installations of NETGEAR R6020, R6080, R6120, R6220, R6260, R6700v2, R6800, R6900v2, R7450, JNR3210, WNR2020, Nighthawk AC2100, and Nighthawk AC2400 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the mini_httpd service, which listens on TCP port 80 by default. The issue results from incorrect string matching logic when accessing protected pages. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of root. Was ZDI-CAN-11355.

Is CVE-2020-27866 actively exploited?

Active exploitation of CVE-2020-27866 has not been confirmed. Its EPSS score was 8.7% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-27866?

CVE-2020-27866 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Hear about the next vulnerability in your software

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 ».

Get alerts for this productCISA KEV additions, November 2026Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database

Sources for this record