What is CVE-2026-73664?

CVE-2026-73664 is FreePBX: Authenticated Arbitrary SSH Key Injection via Backup Module. The supplied enrichment data classifies it as Privilege Esc mapped to CWE-269 Improper Privilege Management; CWE-284 CWE-284; CWE-732 CWE-732.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-73664. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-73664 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

A public PoC is not confirmed from current sources for CVE-2026-73664. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with EDR process telemetry, host service logs where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-73664 using CVSS 8.6, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

highPrivilege Esc

CVE-2026-73664

CVE-2026-73664 — FreePBX: Authenticated Arbitrary SSH Key Injection via Backup Module

FreePBX is an open source IP PBX. From 17.0.5.34 until 17.0.11, the publicKeySave AJAX endpoint in Backup.class.php accepts an authenticated administrator's SSH public key and appends it to /home/asterisk/.ssh/authorized_keys for the asterisk system user without reliably enforcing backup-only command and source restrictions. The key grants persistent shell access that can execute arbitrary commands, access FreePBX and call data, modify system files, and disrupt services. This issue is fixed in version 17.0.11.

Published Aug 13, 2026Updated Aug 13, 2026Sources: NVD, FreePBX (CNA), GitHub, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

ahead of 0% of scored CVEs

Affects

FreePBX

backup

CVSS base

8.6

high

Remediation

The vendor's own words where we have them.

Upgrade backup to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
FreePBX	backup	>= 17.0.5.34, < 17.0.11	Vulnerable

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
8.6	CVSS 4.0	high	—	—	FreePBX (CNA)

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-269 · Improper Privilege Management

Gain Privileges or Assume Identity::

Mitigation: Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.

CWE-732 · Incorrect Permission Assignment for Critical Resource

Read Application Data
Read Files or Directories
Gain Privileges or Assume Identity
Modify Application Data

Mitigation: When using a critical resource such as a configuration file, check to see if the resource has insecure permissions (such as being modifiable by any regular user) [REF-62], and generate an error or even exit the software if there is a possibility that the resource could have been modified by an unauthorized party.

Weakness & attack patterns

CWE-269Improper Privilege Management
CWE-284
CWE-732

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-122 · Privilege AbuseCAPEC-58 · Restful Privilege ElevationCAPEC-233 · Privilege Escalation

T1548Abuse Elevation Control Mechanism
T1027.009Obfuscated Files or Information: Embedded Payloads
T1546.004Event Triggered Execution: .bash_profile and .bashrc

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /home/asterisk/.ssh/authorized_keys.
Review endpoint telemetry for service binary replacement, suspicious service launches, or privilege changes tied to the affected agent.

EDR process telemetryhost service logs

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 8.6
Aug 13, 2026 · NVD
Initial · CVE published
Aug 13, 2026 · NVD

References

1 on the record

github.com/FreePBX/security-reporting/security/advisories/GHSA-24w6-hpg3-rwfg
Exploit, Third Party Advisory, Mitre

Elsewhere on this site

FreePBXevery CVE for this vendor
Privilege Escsame class
CWE-269other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-73664 is FreePBX: Authenticated Arbitrary SSH Key Injection via Backup Module, a high vulnerability affecting backup from FreePBX. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-73664. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-73664. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 8.6 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.