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.
CVE-2026-39894
This low-severity CVE scores 2.5 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 2.5
- EG Score
- 2.5(medium)
- EPSS
- 1.2%
- KEV
- Not listed
Published
June 24, 2026
Last Modified
June 25, 2026
References (3)
- security-advisories@githubhttps://github.com/Cacti/cacti/commit/d2a698854956e9e4e53da9eab5b5719ae40e6893
- security-advisories@githubhttps://github.com/Cacti/cacti/issues/7011
- security-advisories@githubhttps://github.com/Cacti/cacti/security/advisories/GHSA-23g4-vf2j-94w4
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 23× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 05:09 UTCEG score recompute
- 2026-07-08 15:15 UTCEPSS rescore
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 09:12 UTCEG score recompute
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-03 12:49 UTCEG score recompute
- 2026-07-01 15:06 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-30 16:01 UTCEG score recompute
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-27 20:03 UTCEG score recompute▼ 0.40
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-25 21:50 UTCNVD updateCVSS v3 → 2.5
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-25 00:06 UTCEG score recompute
- 2026-06-25 00:03 UTCNVD updatefirst tracked
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Frequently asked(5)
What is CVE-2026-39894?
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-39894
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