CVE-2026-54758Public exploit

Code execution via unbounded variable-name copy

Published Aug 17, 2026 · Updated Aug 17, 2026

Stack buffer overflow in Notepad++ before 8.9.7 allows local users to crash the application and potentially execute code via Run dialog input. In PowerEditor/src/WinControls/StaticDialog/RunDlg/RunDlg.cpp, expandNppEnvironmentStrs copies the variable name between $( and ) into wchar_t str[MAX_PATH] without checking whether m stays below MAX_PATH, so long names overwrite adjacent stack data. Exploitation requires local access and a crafted string reaching the Run dialog path; /GS commonly turns the overwrite into a process-terminating crash, but code execution remains plausible if stack protections are bypassed.

CVSS severity7.8
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in Notepad++ before 8.9.7 allows local users to crash the application and potentially execute code via Run dialog input. In PowerEditor/src/WinControls/StaticDialog/RunDlg/RunDlg.cpp, expandNppEnvironmentStrs copies the variable name between $( and ) into wchar_t str[MAX_PATH] without checking whether m stays below MAX_PATH, so long names overwrite adjacent stack data. Exploitation requires local access and a crafted string reaching the Run dialog path; /GS commonly turns the overwrite into a process-terminating crash, but code execution remains plausible if stack protections are bypassed.

The record

CVE
CVE-2026-54758
Published
Aug 17, 2026
Updated
Aug 17, 2026
Vendor
Notepad++
Product
Notepad++
Classifications
CWE-787, CWE-121
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 17, 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.

  1. Affected versionversion=< 8.9.7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Notepad++ · Notepad++version=< 8.9.7

Published CVSS scores

7.8GitHubCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-121Stack-based Buffer Overflow

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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