CVE-2026-39894 json
Cacti: RRDtool metric shift via LC_NUMERIC locale comma decimal formatting
published 2026-06-24 4 mo ago modified 2026-06-25 4 mo ago also EUVD-2026-39132
- cvss
- 2.9
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.1%
- EPSS 0.1% chance of exploitation in 30 days, percentile 3%
- public exploits
- 0
- none known
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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 2.9 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |
| NVD | 3.1 | 2.5 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N |
Affected products
- Cacti cacti
Classification
- Weakness
-
- CWE-474 Use of Function with Inconsistent Implementations
References
-
github.com
/Cacti/cacti/commit/d2a698854956e9e4e53da9eab5b5719ae40e6893
patch
-
github.com
/Cacti/cacti/issues/7011
issue-tracking, patch
-
github.com
/Cacti/cacti/security/advisories/GHSA-23g4-vf2j-94w4
vendor-advisory
Sources
- CVE List CVE-2026-39894
- NVD CVE-2026-39894
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.