CVE-2026-39894
Cacti: RRDtool metric shift via LC_NUMERIC locale comma decimal formatting
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Low2.9 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | Low2.5 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.14% · top 97% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 2.9.
Weakness
Affected products
References (3)
- https://github.com/Cacti/cacti/security/advisories/GHSA-23g4-vf2j-94w4 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/Cacti/cacti/issues/7011 (opens in a new tab)x_refsource_MISC
- https://github.com/Cacti/cacti/commit/d2a698854956e9e4e53da9eab5b5719ae40e6893 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-39894)Record last updated .