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CVE-2021-45461

35
FAUCET Score

CVE-2021-45461 is a critical remote code execution vulnerability affecting FreePBX and PBXact systems running specific versions of the restapps module (15.0.19.87, 15.0.19.88, 16.0.18.40, 16.0.18.41). With a CVSS score of 9.8, it allows unauthenticated attackers to execute arbitrary code with low attack complexity, leading to complete compromise of confidentiality, integrity, and availability. This vulnerability was actively exploited in the wild in December 2021, as evidenced by media reports detailing campaigns installing PHP web shells on Elastix VoIP systems. While no public exploit code is readily available, the high community discussion and media coverage indicate significant attention to this threat.

Impacted Technologies

VendorProductVersion(s)CPE
15.0.19.87CPE matchmatch criteria
cpe:2.3:a:sangoma:restapps:15.0.19.87:*:*:*:*:*:*:*
15.0.19.88CPE matchmatch criteria
cpe:2.3:a:sangoma:restapps:15.0.19.88:*:*:*:*:*:*:*
16.0.18.40CPE matchmatch criteria
cpe:2.3:a:sangoma:restapps:16.0.18.40:*:*:*:*:*:*:*
16.0.18.41CPE matchmatch criteria
cpe:2.3:a:sangoma:restapps:16.0.18.41:*:*:*:*:*:*:*

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
19.75%
Probability of exploitation in next 30 days
EPSS Percentile
97.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.1975 is in the 94th percentile among its peer group of 36,833 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

community.freepbx.org / t/0-day-freepbx-exploit/80092
ExploitIssue TrackingVendor Advisory
community.freepbx.org / t/security-issue-potential-rest-phone-apps-rce/80109
Vendor Advisory
wiki.freepbx.org / display/FOP/2021-12-21+SECURITY%3A+Potential+Rest+Phone+Apps+RCE
Vendor Advisory