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TI-2026-58869 Aliases CVE-2026-86054

Notepad++: Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path

Priority HIGH 69CWE-121Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-121 and the CVSS impact.

Summary

Notepad++ is a free and open-source source code editor. Prior to 8.9.8, Notepad++ contains a stack buffer overflow in NppParameters::writeSession in PowerEditor/src/Parameters.cpp because it copies a session path derived from -settingsDir= into backupPathName[MAX_PATH] with unbounded wcscpy and appends SESSION_BACKUP_EXT with unbounded wcscat. A sufficiently long settings directory causes the backup suffix to exceed the fixed stack buffer when Notepad++ saves the session, and the protected release build terminates through its stack canary, causing denial of service. This issue is fixed in version 8.9.8.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00228 13th 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
Total

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-2026-86054

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-2026-54091 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
  • TI-2026-04836 Stack-Based Buffer Overflow in Notepad++ File Drop Handler leads to DoS 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