{"id":"CVE-2026-86054","aliases":["EUVD-2026-84572","GHSA-pxgg-96p2-c3hx"],"status":"published","title":"Notepad++: Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path","description":"Notepad++ is a free and open-source source code editor. Prior to 8.9.8, Notepad++ contains a stack buffer overflow in NppParameters::writeSession in PowerEditor/src/Parameters.cpp because it copies a session path derived from -settingsDir= into backupPathName[MAX_PATH] with unbounded wcscpy and appends SESSION_BACKUP_EXT with unbounded wcscat. A sufficiently long settings directory causes the backup suffix to exceed the fixed stack buffer when Notepad++ saves the session, and the protected release build terminates through its stack canary, causing denial of service. This issue is fixed in version 8.9.8.","severity":{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00228,"percentile":0.1369,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-121"],"published":"2026-09-22T17:12:38Z","modified":"2026-10-28T11:01:37Z","products":[{"vendor":"notepad-plus-plus","product":"notepad-plus-plus"}],"references":[{"url":"https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-pxgg-96p2-c3hx","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/notepad-plus-plus/notepad-plus-plus/commit/046af3f626be7715886412313fc18f58b30dfcaf","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8","tags":["x_refsource_MISC","web"]},{"url":"https://notepad-plus-plus.org/news/v898-released","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86054.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86054","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-86054","title":"Notepad++: Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path","description":"Notepad++ is a free and open-source source code editor. Prior to 8.9.8, Notepad++ contains a stack buffer overflow in NppParameters::writeSession in PowerEditor/src/Parameters.cpp because it copies a session path derived from -settingsDir= into backupPathName[MAX_PATH] with unbounded wcscpy and appends SESSION_BACKUP_EXT with unbounded wcscat. A sufficiently long settings directory causes the backup suffix to exceed the fixed stack buffer when Notepad++ saves the session, and the protected release build terminates through its stack canary, causing denial of service. This issue is fixed in version 8.9.8.","status":"published","published":"2026-09-22T17:12:38.351Z","modified":"2026-09-28T17:36:02.778Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-121"],"updated_at":"2026-11-02T13:49:42.666099Z"}],"euvd":[{"id":"EUVD-2026-84572","description":"Notepad++ is a free and open-source source code editor. Prior to 8.9.8, Notepad++ contains a stack buffer overflow in NppParameters::writeSession in PowerEditor/src/Parameters.cpp because it copies a session path derived from -settingsDir= into backupPathName[MAX_PATH] with unbounded wcscpy and appends SESSION_BACKUP_EXT with unbounded wcscat. A sufficiently long settings directory causes the backup suffix to exceed the fixed stack buffer when Notepad++ saves the session, and the protected release build terminates through its stack canary, causing denial of service. This issue is fixed in version 8.9.8.","status":"published","published":"2026-09-22T17:12:38Z","modified":"2026-09-28T17:36:02Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T17:27:53.091489Z"}],"nvd":[{"id":"CVE-2026-86054","description":"Notepad++ is a free and open-source source code editor. Prior to 8.9.8, Notepad++ contains a stack buffer overflow in NppParameters::writeSession in PowerEditor/src/Parameters.cpp because it copies a session path derived from -settingsDir= into backupPathName[MAX_PATH] with unbounded wcscpy and appends SESSION_BACKUP_EXT with unbounded wcscat. A sufficiently long settings directory causes the backup suffix to exceed the fixed stack buffer when Notepad++ saves the session, and the protected release build terminates through its stack canary, causing denial of service. This issue is fixed in version 8.9.8.","status":"published","published":"2026-09-22T18:17:23.827Z","modified":"2026-09-28T18:17:25.42Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-121"],"updated_at":"2026-11-02T14:12:50.368368Z"}],"osv":[{"id":"CVE-2026-86054","title":"Notepad++: Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path","description":"Notepad++ is a free and open-source source code editor. Prior to 8.9.8, Notepad++ contains a stack buffer overflow in NppParameters::writeSession in PowerEditor/src/Parameters.cpp because it copies a session path derived from -settingsDir= into backupPathName[MAX_PATH] with unbounded wcscpy and appends SESSION_BACKUP_EXT with unbounded wcscat. A sufficiently long settings directory causes the backup suffix to exceed the fixed stack buffer when Notepad++ saves the session, and the protected release build terminates through its stack canary, causing denial of service. This issue is fixed in version 8.9.8.","status":"published","published":"2026-09-22T17:12:38.351Z","modified":"2026-10-28T11:01:37.97183003Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-121"],"updated_at":"2026-11-02T15:45:18.825071Z"}]}}