Cacti: RRDtool metric shift via LC_NUMERIC locale comma decimal formatting

{
  "id": "ff3d1509acd396a1a6a866dd25f82658530983a5e64a5c054463ab7632846646",
  "url": "https://osv.dev/vulnerability/CVE-2026-39894",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Cacti: RRDtool metric shift via LC_NUMERIC locale comma decimal formatting",
    "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.",
    "evidence": "osv:CVE-2026-39894",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CVE-2026-39894",
      "aliases": [
        "CVE-2026-39894",
        "GHSA-23g4-vf2j-94w4"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/cacti/cacti",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1e8eaca26b84b128c39ce8cc8ece42d7ff76aac1"
                },
                {
                  "fixed": "d2a698854956e9e4e53da9eab5b5719ae40e6893"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:cacti:cacti:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.2.31"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "d2a698854956e9e4e53da9eab5b5719ae40e6893"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
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            "releaes/1.2.19",
            "release/1.2.18",
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            "rel-1.2.17",
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            "release/1.0.3",
            "release/1.0.2",
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-39894.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.941269208Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39894.json",
        "https://github.com/Cacti/cacti/security/advisories/GHSA-23g4-vf2j-94w4",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-39894",
        "https://github.com/Cacti/cacti/issues/7011",
        "https://github.com/Cacti/cacti/commit/d2a698854956e9e4e53da9eab5b5719ae40e6893"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-474"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39894.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-39894",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 506025,
  "published_at": "2026-06-24T21:55:49.857+00:00"
}