Is CVE-2026-86054 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-86054 being exploited in the wild.

How severe is CVE-2026-86054?

High severity, with a CVSS score of 7.8, published 22 September 2026.

Which products and versions are affected?

Notepad++ Notepad++ before 8.9.8.

Is there a fix for CVE-2026-86054?

A patch was published on 2026-08-23: version 8.9.8 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-86054 attacked?

It is attacked with local access.

Am I affected by CVE-2026-86054?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-86054: Notepad++ stack buffer overflow in session path handling

CVE-2026-86054 · Severity: high · CVSS 7.8 · Published 2026-09-22

Notepad++, a widely-used source code editor, contains a stack buffer overflow vulnerability in how it handles session file paths. An attacker can provide an overly long settings directory path via the -settingsDir command-line argument, causing the application to crash with a denial of service when it attempts to save the session. The protected build's stack canary prevents code execution, but the crash prevents legitimate use.

Quick answers

Is CVE-2026-86054 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-86054 being exploited in the wild.
How severe is CVE-2026-86054?: High severity, with a CVSS score of 7.8, published 22 September 2026.
Which products and versions are affected?: Notepad++ Notepad++ before 8.9.8.
Is there a fix for CVE-2026-86054?: A patch was published on 2026-08-23: version 8.9.8 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-86054 attacked?: It is attacked with local access.
Am I affected by CVE-2026-86054?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in NppParameters::writeSession in PowerEditor/src/Parameters.cpp, where user-controlled session paths derived from the -settingsDir command-line parameter are copied into a fixed-size stack buffer (backupPathName[MAX_PATH]) using unbounded wcscpy and wcscat functions. A sufficiently long settings directory path causes the SESSION_BACKUP_EXT suffix to overflow the buffer, triggering a stack canary check in protected builds and terminating the process. The fix, applied in version 8.9.8, uses bounded string functions to prevent the overflow.

Affected products

Notepad++ Notepad++ before 8.9.8

Timeline

2026-09-22: disclosed
2026-08-23: patched: version 8.9.8 released

References

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