PatchTheCVECVE-2026-86054: Notepad++ is a free and open-source source code editor
CVE-2026-86054 is a high-severity flaw (CVSS 7.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 No
Why this priority
- High severity
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 7.8 (High) |
| Attack vector | Local |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 0.2% (top 87%) |
| CISA exploited list | No |
| Weakness | CWE-121 |
| Published | 2026-09-22 |
| Last modified | 2026-09-28 |
Last updated 2026-09-28 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-86054?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-86054 being exploited?
CVE-2026-86054 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-86054 affect?
CVE-2026-86054 affects affected software. Severity is high (CVSS 7.8). 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=
How urgent is CVE-2026-86054?
Priority 31/100. High severity