CVE-2023-40036Public exploit

Out-of-bounds read via mismatched character-frequency bounds

Published Aug 25, 2023 · Updated Oct 1, 2024

Global buffer read overflow in Notepad++ 8.5.6 and earlier allows attackers to trigger an out-of-bounds read with a crafted file. CharDistributionAnalysis::HandleOneChar checks an input-derived order against mTableSize, whose value exceeds the 5,376-element mCharToFreqOrder array. A user must open the file; public analysis confirms the read but does not establish reliable recovery of memory contents.

CVSS severity5.5
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Global buffer read overflow in Notepad++ 8.5.6 and earlier allows attackers to trigger an out-of-bounds read with a crafted file. CharDistributionAnalysis::HandleOneChar checks an input-derived order against mTableSize, whose value exceeds the 5,376-element mCharToFreqOrder array. A user must open the file; public analysis confirms the read but does not establish reliable recovery of memory contents.

The record

CVE
CVE-2023-40036
Published
Aug 25, 2023
Updated
Oct 1, 2024
Vendor
Notepad++
Product
Notepad++
Classifications
CWE-120
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 2024Record 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=<= 8.5.6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Notepad++ · Notepad++version=<= 8.5.6

Published CVSS scores

5.5GitHub CNACVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
5.5NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic 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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