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CVE-2021-27255

28
FAUCET Score

CVE-2021-27255 is a critical authentication bypass vulnerability affecting NETGEAR R7800 firmware version 1.0.2.76. It allows unauthenticated remote attackers to execute arbitrary code with root privileges by exploiting the refresh_status.aspx endpoint. This vulnerability has a CVSS score of 8.8 (High) due to its low attack complexity and complete compromise of confidentiality, integrity, and availability. While no public exploits or active exploitation have been observed, and community discussion is minimal, the potential for severe impact warrants attention.

Impacted Technologies

VendorProductVersion(s)CPE
< 5.10.0.5CPE matchmatch criteria
cpe:2.3:o:netgear:br200_firmware:*:*:*:*:*:*:*:*
< 5.10.0.5CPE matchmatch criteria
cpe:2.3:o:netgear:br500_firmware:*:*:*:*:*:*:*:*
< 1.0.1.60CPE matchmatch criteria
cpe:2.3:o:netgear:d7800_firmware:*:*:*:*:*:*:*:*
< 1.0.1.98CPE matchmatch criteria
cpe:2.3:o:netgear:ex6100v2_firmware:*:*:*:*:*:*:*:*
< 1.0.1.98CPE matchmatch criteria
cpe:2.3:o:netgear:ex6150v2_firmware:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

6.3MEDIUM

CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
LOW
Exploitability Score
2.8
Impact Score
3.4
CvssVersion
3.0

Exploit Intelligence

EPSS Score
1.26%
Probability of exploitation in next 30 days
EPSS Percentile
66.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0126 is in the 81st percentile among its peer group of 1,875 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.2 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

kb.netgear.com / 000062883/Security-Advisory-for-Multiple-Vulnerabilities-on-Some-Routers-Satellites-and-Extenders
PatchVendor Advisory
zerodayinitiative.com / advisories/ZDI-21-263
Third Party AdvisoryVDB Entry