VulnerabilityAnalyzed

CVE-2026-39894

In versions 1.2.30 and below, the locale-dependent decimal formatting in rrdtool_function_update() can corrupt RRDtool metric values.

LOW 2.5EPSS 0.14%

Does this matter?

Lower severity and a low EPSS score (0.14%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 3.1: 2.5 LOWCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
EPSS: 0.14% probability · 4th percentile
CISA KEV: Not listed
Weakness: CWE-474
Affected: cacti/cacti
Source: security-advisories@github.com

References

https://github.com/Cacti/cacti/commit/d2a698854956e9e4e53da9eab5b5719ae40e6893Patch
https://github.com/Cacti/cacti/issues/7011Issue Tracking, Patch
https://github.com/Cacti/cacti/security/advisories/GHSA-23g4-vf2j-94w4Vendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.