CVE-2026-39894

Name	CVE-2026-39894
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
cacti (PTS)	bullseye	1.2.16+ds1-2+deb11u3	vulnerable
	bullseye (security)	1.2.16+ds1-2+deb11u5	vulnerable
	bookworm, bookworm (security)	1.2.24+ds1-1+deb12u5	vulnerable
	trixie	1.2.30+ds1-1	vulnerable
	forky, sid	1.2.30+ds1-3	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
cacti	source	(unstable)	(unfixed)

Notes

https://github.com/Cacti/cacti/security/advisories/GHSA-23g4-vf2j-94w4
https://github.com/Cacti/cacti/issues/7011
Fixed by: https://github.com/Cacti/cacti/commit/d2a698854956e9e4e53da9eab5b5719ae40e6893 (release/1.2.31)