Editor crash via overlong session backup path
Published Sep 22, 2026 · Updated Sep 22, 2026
Stack-based buffer overflow in Notepad++ before 8.9.8 allows local users to crash the editor through an overlong settings directory. NppParameters::writeSession copies the derived session path into backupPathName[MAX_PATH] with unbounded wcscpy, then appends the backup suffix with unbounded wcscat. Exploitation requires launching Notepad++ with a sufficiently long -settingsDir= path and saving a session; the protected release build terminates through its stack canary.
Summary
What happened
Stack-based buffer overflow in Notepad++ before 8.9.8 allows local users to crash the editor through an overlong settings directory. NppParameters::writeSession copies the derived session path into backupPathName[MAX_PATH] with unbounded wcscpy, then appends the backup suffix with unbounded wcscat. Exploitation requires launching Notepad++ with a sufficiently long -settingsDir= path and saving a session; the protected release build terminates through its stack canary.
The record
- CVE
- CVE-2026-86054
- Published
- Sep 22, 2026
- Updated
- Sep 22, 2026
- Vendor
- Notepad++
- Product
- Notepad++
- Classifications
- CWE-121
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 22, 2026CVE publishedPublication date reported by the CVE source.
- Sep 22, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 8.9.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- GHSA-pxgg-96p2-c3hx crash proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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