CVE-2026-26978
CWE-502Published: May 18, 2026· Updated: May 19, 2026
Official Description
FreePBX is an open source IP PBX. In versions below 16.0.71 and 17.0.6, the backup module does not properly sanitize data during restore operations, potentially leading to compromise if the backup contains carefully crafted hostile data. During backup restore operations, FreePBX extracts selected files from a user-supplied tar archive. If a malicious file exists in the archive, it is read and passed directly to unserialize() without validation, class restrictions, or integrity checks. This issue allows Remote Code Execution during restoration of the backup as the web server user (typically asterisk or www-data). The attack does not require shell access, CLI access, or filesystem write permissions beyond the normal restore workflow. Authentication with a known username that has sufficient access permissions and/or write access to backup files is required. This issue has been fixed in versions 16.0.71 and 17.0.6.
Technical Analysis
CVE-2026-26978 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
From a weakness classification perspective (CWE-502): Insecure deserialization vulnerabilities allow attackers to inject malicious objects during deserialization, potentially enabling remote code execution.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (3)
Quick Facts
Related CVEs (CWE-502)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-26978 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts