CVE-2026-39894

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.

Affected Software

VendorProductVersion RangeStatus
Cacticacti< 1.2.31affected

Weaknesses

  • CWE-474: CWE-474: Use of Function with Inconsistent Implementations

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References