Executive brief
Cacti is an open-source platform used for monitoring network performance and managing system faults. A technical issue in how the software handles numbers on servers configured with certain international regional settings (locales) can cause monitoring data to become corrupted or misaligned. While this does not allow an outside attacker to steal data, it can lead to inaccurate reporting and loss of historical performance metrics, potentially impacting operational decision-making.
Technical details
The vulnerability exists in the `rrdtool_function_update()` function within `lib/rrd.php`. The application uses PHP string interpolation to construct RRDtool update commands. Because PHP's float-to-string conversion is locale-sensitive, servers configured with an `LC_NUMERIC` locale that uses commas as decimal separators (e.g., German or French) will produce strings like '1,5' instead of '1.5'. Since RRDtool strictly expects a period as the decimal separator, this causes the command parser to shift metric data into incorrect columns or drop the data entirely. This is a data integrity issue that requires a specific server locale configuration to manifest. The issue is addressed in version 1.2.31 by enforcing strict dot-decimal formatting at the IPC boundary.
Affected products
- Cacti Cacti <= 1.2.30
Timeline
- 2026-04-06: disclosed: Issue reported via GitHub
- 2026-06-18: advisory: Project security advisory published
- 2026-06-24: patched: CVE published and fix confirmed in version 1.2.31