Cacti: RRDtool metric shift via LC_NUMERIC locale comma decimal formatting
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA cacti (Cacti) Fixed in 1.2.31
Timeline
- 2026-10-02 Threatist record created from CVE-2026-39894
References
More Cacti vulnerabilities
- TI-2022-22813 Unauthenticated command injection in cacti KEVCVSS 3.1CRITICAL 9.8
- TI-2023-20500 Unauthenticated SQL Injection in graph_view.php in Cacti CVSS 3.1CRITICAL 9.8
- TI-2024-16869 Cacti RCE vulnerability when importing packages CVSS 3.1CRITICAL 9.1
- TI-2024-20809 SQL Injection vulnerability in automation_get_new_graphs_sql CVSS 3.1HIGH 8.8
- TI-2023-26750 Cacti SQL Injection vulnerability CVSS 3.1HIGH 8.8
- TI-2025-18110 Cacti allows Arbitrary File Creation leading to RCE CVSS 4.0HIGH 8.7
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences