Notepad++ 8.9.3 Format String Injection via nativeLang.xml

{
  "id": "5a9a18cb23827aa9a7771050ce3860b95d1ef4766748ee8ddc835cfeb50bd360",
  "url": "https://osv.dev/vulnerability/CVE-2026-6539",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Notepad++ 8.9.3 Format String Injection via nativeLang.xml",
    "summary": "Notepad++ 8.9.3 contains a format string injection vulnerability in the Find Results panel handler that allows attackers to cause denial of service and information disclosure by crafting a malicious nativeLang.xml language pack file. Attackers can distribute a poisoned language pack through community channels that triggers format string interpretation when a user performs search operations, leading to access violations and potential leakage of stack or register contents.",
    "evidence": "osv:CVE-2026-6539",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-6539",
      "aliases": [
        "CVE-2026-6539"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/notepad-plus-plus/notepad-plus-plus",
              "type": "GIT",
              "events": [
                {
                  "introduced": "8452101a4b349c46b19af7d7010588d3b540294f"
                },
                {
                  "last_affected": "8452101a4b349c46b19af7d7010588d3b540294f"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:notepad-plus-plus:notepad\\+\\+:8.9.3:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "8.9.3"
                      },
                      {
                        "last_affected": "8.9.3"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "8.9.3",
            "v8.9.3"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-6539.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:39.836731052Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6539.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-6539",
        "https://www.vulncheck.com/advisories/notepad-format-string-injection-via-nativelang-xml",
        "https://notepad-plus-plus.org/news/v894-released/"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-134"
        ],
        "cna_assigner": "VulnCheck",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "fixed": "8.9.4"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6539.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-6539",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 507344,
  "published_at": "2026-04-30T20:31:54.961+00:00"
}