CVE-2026-26978 Free PBX backup: Deserialization of Untrusted Data in admin/modules/backup/Models/BackupSplFileInfo.php
Authenticated attackers can achieve remote code execution by restoring a malicious backup archive containing crafted serialized data.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-26978?
CVE-2026-26978 is a high-severity unsafe deserialization vulnerability in FreePBX security-reporting, published on 18 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
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.
Weakness: CWE-502
Which versions are affected by CVE-2026-26978?
How do I fix CVE-2026-26978?
No fix has been published for CVE-2026-26978 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-26978 being exploited?
There is no known exploitation of CVE-2026-26978 in the wild and no public exploit code.
Sources
Also known as GHSA-5v7h-49gr-jcwr.