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CVE-2021-27104

89
FAUCET Score

CVE-2021-27104 is a critical OS command injection vulnerability (CVSS 9.8) affecting Accellion FTA versions 9_12_370 and earlier, allowing unauthenticated attackers to execute arbitrary commands via crafted POST requests to administrative endpoints. This flaw is easily exploitable over the network with low attack complexity, leading to complete compromise of confidentiality, integrity, and availability. The vulnerability is actively exploited in the wild, notably by ransomware groups, and has garnered significant community attention and media coverage, despite a lack of public exploit code in common repositories.

Impacted Technologies

VendorProductVersion(s)CPE
<= 9_12_370CPE matchmatch criteria
cpe:2.3:a:accellion:fta:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
56.41%
Probability of exploitation in next 30 days
EPSS Percentile
99.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Added to KEV · Nov 3, 2021
This CVE's current EPSS score of 0.5641 is in the 97th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
github.com / accellion/CVEs/blob/main/CVE-2021-27104.txt
Broken LinkThird Party Advisory
accellion.com / products/fta
ProductVendor Advisory