CVE-2026-86054

Description

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.

Overview

State: PUBLISHED
Assigner (CNA): GitHub_M
CVSS severity: HIGH
CVSS score: 7.8 / 10
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Effective score: 7.8 / 10 HIGH source: CNA overview
CWE(s): CWE-121
Reserved: 2026-09-04
Published: 2026-09-22 17:12 UTC
Last updated: 2026-09-22 17:12 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/86xxx/CVE-2026-86054.json
Linked Threat: CVE-2026-86054 — Notepad++: Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-22 18:17:23 UTC
NVD last modified: 2026-09-22 18:17:23 UTC
NVD CVSS v3.1: 7.8 / 10 HIGH source: security-advisories@github.com
NVD CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploitability subscore: 1.8 / 10
Impact subscore: 5.9 / 10

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-84572
Assigner: GitHub_M
Published: Sep 22, 2026, 5:12:38 PM
Updated: Sep 22, 2026, 5:12:38 PM
EUVD base score (CVSS 3.1): 7.8 / 10
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EUVD-reported EPSS: 0.0000
Vendors: notepad-plus-plus
Products: notepad-plus-plus (< 8.9.8)

ENISA description: 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.

EUVD references (4)

Affected products (1)

Vendor	Product	Versions	Platforms
notepad-plus-plus	notepad-plus-plus	`< 8.9.8` (affected)	—

Vendor references (4)

References embedded in the original CVE record by the assigning CNA.

https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-pxgg-96p2-c3hx x_refsource_CONFIRM
https://github.com/notepad-plus-plus/notepad-plus-plus/commit/046af3f626be7715886412313fc18f58b30dfcaf x_refsource_MISC
https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8 x_refsource_MISC
https://notepad-plus-plus.org/news/v898-released x_refsource_MISC

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (4)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://github.com/notepad-plus-plus/notepad-plus-plus/commit/046af3f626be7715886412313fc18f58b30dfcaf security-advisories@github.com
https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8 security-advisories@github.com
https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-pxgg-96p2-c3hx security-advisories@github.com
https://notepad-plus-plus.org/news/v898-released security-advisories@github.com

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Microsoft Update Catalog

web:catalog.update.microsoft.com

Welcome to the Microsoft Update Catalog site. We want your feedback! Visit our newsgroup or send us an email to provide us with your thoughts and suggestions. To get started using the site, enter in your search terms in the Search box above or visit our FAQ for search tips. |Newsgroup|Send us your feedback

2026-09-23 15:14 UTC
CVE-2026-86054: Notepad Plus Plus Buffer Overflow | CVETodo

web:cvetodo.com

CVE-2026-86054 is a CVSS 7.8 Buffer Overflow vulnerability in Notepad Plus Plus. Includes technical details, affected versions, and mitigation steps.

2026-09-23 15:14 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Access Microsoft Security Response Center's guide to address vulnerabilities, manage security risks, and keep your systems protected with the latest updates.

2026-09-23 15:14 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Security Update Guide - Microsoft Security Response Center

2026-09-23 15:14 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-23 15:14 UTC
Description of the security update for Office 2016: August 11, 2026 ...

web:support.microsoft.com

Be aware that the update in the Microsoft Download Center applies to the Microsoft Installer (.msi)-based edition of Office 2016. It doesn't apply to the Office 2016 Click-to-Run editions, such as Microsoft Office 365 Home. (See What version of Office am I using?) How to get and install the update Method 1: Microsoft Update This update is available from Microsoft Update. When you turn on ...

2026-09-23 15:14 UTC
August 2026 CVE Advisory Notification - Security

web:support.servicenow.com

Due to additional analysis provided by the security researcher who discovered CVE - 2026 -6876, we have upgraded the severity rating of CVE - 2026 -6876 from High to Critical. This change affects only the severity

2026-09-23 15:14 UTC
CVE-2026-86054 - Notepad++ Stack Buffer Overflow Leads to…

web:vulmon.com

Vulnerability Summary Notepad++ versions prior to 8.9.8 are vulnerable to a stack buffer overflow in NppParameters::writeSession. This flaw occurs when a long session path derived from -settingsDir= is copied into a fixed-size buffer, and the SESSION_BACKUP_EXT is appended without bounds checking. This condition can cause the program to terminate, resulting in a denial of service. The issue is ...

2026-09-23 15:14 UTC
CVE-2026-86054 - Detail CVSS, EPSS & CISA Kev | CVE Find

web:www.cvefind.com

Full details for CVE-2026-86054 : technical description, impact, CVSS/EPSS scores, linked CWE, CAPEC, affected CPEs, disclosure date, and mitigation options.

2026-09-23 15:14 UTC
CVE-2026-86054: notepad-plus-plus: Notepad++ is a free and ... - Rapid7

web:www.rapid7.com

CVE-2026-86054 : notepad-plus-plus: Notepad++ is a free and open-source source code editor. View severity, references, and remediation details from Rapid7.

2026-09-23 15:14 UTC

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-86054.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "notepad-plus-plus",
          "vendor": "notepad-plus-plus",
          "versions": [
            {
              "status": "affected",
              "version": "< 8.9.8"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-121",
              "description": "CWE-121: Stack-based Buffer Overflow",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-22T17:12:38.351Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-pxgg-96p2-c3hx",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-pxgg-96p2-c3hx"
        },
        {
          "name": "https://github.com/notepad-plus-plus/notepad-plus-plus/commit/046af3f626be7715886412313fc18f58b30dfcaf",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/notepad-plus-plus/notepad-plus-plus/commit/046af3f626be7715886412313fc18f58b30dfcaf"
        },
        {
          "name": "https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8"
        },
        {
          "name": "https://notepad-plus-plus.org/news/v898-released",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://notepad-plus-plus.org/news/v898-released"
        }
      ],
      "source": {
        "advisory": "GHSA-pxgg-96p2-c3hx",
        "discovery": "UNKNOWN"
      },
      "title": "Notepad++: Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-86054",
    "datePublished": "2026-09-22T17:12:38.351Z",
    "dateReserved": "2026-09-04T19:29:21.059Z",
    "dateUpdated": "2026-09-22T17:12:38.351Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}