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TI-2026-58870 Aliases CVE-2026-86056

Notepad++: Null pointer dereference in NPPM_SAVESESSION message handler causes crash (DoS)

Priority MEDIUM 58CWE-476Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-476.

Summary

Notepad++ is a free and open-source source code editor. Prior to 8.9.8, the NPPM_SAVESESSION handler in PowerEditor/src/NppBigSwitch.cpp converts lParam to a sessionInfo pointer and dereferences its nbFile, files, and sessionFilePathName members without checking for null. A process running at the same or a higher Windows integrity level on the same desktop can send NPPM_SAVESESSION with a null lParam, immediately terminating Notepad++ and causing denial of service and loss of unsaved documents. This issue is fixed in version 8.9.8.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00162 5th percentileScored 2026-11-07
Fix Fixed notepad-plus-plus (notepad-plus-plus): 8.9.8

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
notepad-plus-plusnotepad-plus-plusbefore 8.9.88.9.8Patch availableCNA
  • notepad-plus-plus Vendornotepad-plus-plus Affected before 8.9.8 Fixed in 8.9.8 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:notepad-plus-plus:notepad\+\+:*:*:*:*:*:*:*:*——notepad-plus-plus
  • cpe:2.3:a:notepad-plus-plus:notepad\+\+:*:*:*:*:*:*:*:* Versions — — ·notepad-plus-plus

Remediation

  • Fix · CNA notepad-plus-plus (notepad-plus-plus) Fixed in 8.9.8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-86056

References

Other 4

  • TI-2025-14195 Notepad++ < 8.8.9 WinGUp Updater Lacks Update Integrity Verification KEVCVSS 4.0HIGH 7.7
  • TI-2026-58566 Notepad++: Stack Buffer Overflow in Plugin Lexer Loading via Unchecked GetLexerCount() Return Value CVSS 3.1HIGH 8.6
  • TI-2026-58869 Notepad++: Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path CVSS 3.1HIGH 7.8
  • TI-2026-54091 Notepad++ “Run by system” executes *.txt.cmd when user selected *.txt (target confusion → command execution) CVSS 3.1HIGH 7.8
  • TI-2026-36070 Notepad++: Arbitrary Code Execution via shortcuts.xml UserCommand Injection CVSS 3.1HIGH 7.8
  • TI-2026-36048 Notepad++: Arbitrary Code Execution via config.xml commandLineInterpreter CVSS 3.1HIGH 7.8
See all 31 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences