CVE-2026-73663: FreePBX is an open source IP PBX

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CRITICAL 9.8REMOTEUPGRADE

CVE-2026-73663 is a critical-severity flaw (CVSS 9.8) affecting freepbx. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FreePBX is an open source IP PBX. From 16.0.0 until 16.0.11 and 17.0.4, the FreePBX missedcall module places the inbound Caller ID name from crafted SIP From headers into the missedcalllog INSERT in agi-bin/missedcallnotify.php without escaping or bound parameters. An unauthenticated caller can inject SQL when a monitored extension goes unanswered, corrupting the database and modifying FreePBX administrator accounts to obtain unauthorized remote

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-89
Published	2026-08-13
Last modified	2026-10-09

Publisher (CNA): GitHub, Inc. · Vendor: sangoma

Last updated 2026-10-09 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-13 22:17 UTCPublished CVE record published
2026-10-09 19:31 UTCUpdated Record last modified

sangoma freepbx UPGRADE

Affected: >= 16.0 and < 16.0.11 · >= 17.0 and < 17.0.4

Fixed in: 16.0.11, 17.0.4

Safe to downgrade to: a release before 16.0

1. Check installed version

apt-cache policy freepbx || rpm -q freepbx || freepbx --version

2. UPGRADE to 16.0.11 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade freepbx

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade freepbx

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 16.0 (Debian / Ubuntu)

apt-cache madison freepbx sudo apt install freepbx=<VERSION_BEFORE_16.0> sudo apt-mark hold freepbx

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list freepbx sudo dnf downgrade freepbx-<VERSION_BEFORE_16.0> sudo dnf versionlock add freepbx

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-73663?

freepbx: upgrade to 16.0.11, 17.0.4. Exact commands for each OS are on this page.

Is CVE-2026-73663 being exploited?

CVE-2026-73663 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-73663 affect?

CVE-2026-73663 affects freepbx. Severity is critical (CVSS 9.8). FreePBX is an open source IP PBX. From 16.0.0 until 16.0.11 and 17.0.4, the FreePBX missedcall module places the inbound Caller ID name from crafted SIP From headers into the missedcalllog INSERT in agi-bin/missedcallnotify.php without esca

How urgent is CVE-2026-73663?

Priority 47/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

Related CVEs

CVE-2026-45562 HIGH 7.2 UPGRADE FreePBX is an open source IP PBX
CVE-2026-54674 HIGH 8.8 UPGRADE FreePBX is an open source IP PBX
CVE-2026-54675 HIGH 8.8 UPGRADE FreePBX is an open source IP PBX
CVE-2026-54708 HIGH 8.8 UPGRADE FreePBX is an open source IP PBX
CVE-2026-54710 HIGH 8.8 UPGRADE FreePBX is an open source IP PBX

References

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