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Fencer Vulns
high 8.6

CVE-2026-26978 json

Free PBX backup: Deserialization of Untrusted Data in admin/modules/backup/Models/BackupSplFileInfo.php

published 2026-05-18 5 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-30810

cvss
8.6
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 59%
public exploits
0
none known

Summary

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.

Patch / fix

  • freepbx backup 16.0.71, 17.0.6

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
5 mo ago

Exploit prediction

0.90% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 4.0 8.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • FreePBX security-reporting

Classification

Weakness
  • CWE-502 Deserialization of Untrusted Data

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.