CVE-2026-39894 Details
Description
Cacti is an open source performance and fault management framework. In versions 1.2.30 and below, the locale-dependent decimal formatting in rrdtool_function_update() can corrupt RRDtool metric values. The rrdtool_function_update() function checks metric values with is_numeric() and concatenates them into the RRDtool update command via PHP string interpolation. PHP's string cast of floats is locale-sensitive: if LC_NUMERIC uses comma as decimal separator (e.g., de_DE), a value of 1.5 becomes "1,5". RRDtool expects . as decimal separator, causing metric data to shift into wrong columns or be silently dropped. No setlocale() reset is present in the update path. This causes a data integrity issue, but is not remotely exploitable; it requires server locale misconfiguration. The issue has been fixed in version 1.2.31.
A data integrity vulnerability has been identified in Cacti versions through 1.2.30. The issue arises in the 'rrdtool_function_update()' metric serialization process, where locale-dependent decimal formatting can distort RRDtool metric values. This vulnerability is not remotely exploitable and requires a server locale misconfiguration that uses commas as decimal separators. The absence of a 'setlocale()' reset in the update path exacerbates the problem.
Users can update to Cacti version 1.2.31, where this vulnerability has been fixed. The update is available on the Cacti GitHub repository.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 25, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-474 | Use of Function with Inconsistent Implementations | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| cacti cacti | < 1.2.31 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 25, 2026 | Initial Analysis | [email protected] |
| Jun 25, 2026 | CVE Modified | CISA-ADP |
| Jun 24, 2026 | New CVE Received | [email protected] |