CVE-2026-48770Public exploitHinoki check available

Local crash via unbounded WM_COPYDATA string

Published Jun 26, 2026 · Updated Jun 26, 2026

Out-of-bounds read in Notepad++ before 8.9.6.1 allows local users to crash the editor through a malformed WM_COPYDATA message. The COPYDATA_FULL_CMDLINE handler passes COPYDATASTRUCT.lpData to setCmdLineString as an unbounded NUL-terminated wide string without enforcing cbData. Exploitation requires a running Notepad++ window and a process in the same interactive Windows session; the bounded consequence is a reliable editor crash.

CVSS severity5.0
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Out-of-bounds read in Notepad++ before 8.9.6.1 allows local users to crash the editor through a malformed WM_COPYDATA message. The COPYDATA_FULL_CMDLINE handler passes COPYDATASTRUCT.lpData to setCmdLineString as an unbounded NUL-terminated wide string without enforcing cbData. Exploitation requires a running Notepad++ window and a process in the same interactive Windows session; the bounded consequence is a reliable editor crash.

The record

CVE
CVE-2026-48770
Published
Jun 26, 2026
Updated
Jun 26, 2026
Vendor
Notepad++
Product
Notepad++
Classifications
CWE-125, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 26, 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=< 8.9.6.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Notepad++ · Notepad++version=< 8.9.6.1

Published CVSS scores

5.0GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

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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