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CVE-2021-28976

34
FAUCET Score

CVE-2021-28976 is a Remote Code Execution (RCE) vulnerability affecting GetSimpleCMS versions prior to 3.3.16, specifically within the admin/upload.php component through the use of PHAR files. This high-severity vulnerability, rated 7.2 CVSSv3.1, allows an authenticated attacker with high privileges to execute arbitrary code remotely with low attack complexity, leading to complete compromise of confidentiality, integrity, and availability. While not listed in CISA's KEV catalog, an exploit module is publicly available on ExploitDB (EDB-52168), indicating the potential for exploitation. Despite this, there is currently no evidence of active exploitation, Metasploit or Nuclei modules, or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 3.3.15CPE matchmatch criteria
cpe:2.3:a:get-simple:getsimplecms:*:*:*:*:*:*:*:*

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
7.55%
Probability of exploitation in next 30 days
EPSS Percentile
93.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
ExploitDB: EDB-52168 · Apr 11, 2025
This CVE's current EPSS score of 0.0755 is in the 92nd percentile among its peer group of 5,537 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

Patch Available

Remediation records are not available for this CVE.

References

github.com / GetSimpleCMS/GetSimpleCMS/issues/1335
Third Party Advisory