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CVE-2021-37770

24
FAUCET Score

CVE-2021-37770 describes a high-severity file upload vulnerability in Nucleus CMS v3.71. An authenticated attacker can manipulate the upload path to bypass .htaccess protections, upload a malicious .htaccess file to enable PHP execution for image files, and then upload a web shell disguised as an image. This allows for arbitrary command execution, leading to full compromise of website resources. While the CVSS score is 7.2, there is no evidence of active exploitation, public exploit code, or significant community discussion, suggesting a lower immediate threat despite the high potential impact.

Impacted Technologies

VendorProductVersion(s)CPE
3.71CPE matchmatch criteria
cpe:2.3:a:nucleuscms:nucleus_cms:3.71:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.2HIGH

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.2
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.27%
Probability of exploitation in next 30 days
EPSS Percentile
66.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0127 is in the 57th percentile among its peer group of 5,531 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.3 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

github.com / NucleusCMS/NucleusCMS/issues/96
ExploitIssue TrackingThird Party Advisory
shimo.im / docs/Ch9CphJt8XwTvQ3d
ExploitThird Party Advisory