CVE-2026-86054

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (12th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.8Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
7.8
EG Score
7.8HIGHmedium confidence
EG Risk
51
EG Risk 51/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.2%
EPSS %ILE
12th
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 22, 2026

Last Modified

September 28, 2026

Advisory Details (4)

Auto-updated Sep 22, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
generic

Notepad++ v8.9.8 release | Notepad++

https://notepad-plus-plus.org/news/v898-released
github_release Patch Available

Notepad++ release 8.9.8

Patch available: notepad-plus-plus/notepad-plus-plus v8.9.8

https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8
github_commit

commit 046af3f626be (notepad-plus-plus/notepad-plus-plus)

Fix landed in notepad-plus-plus/notepad-plus-plus commit 046af3f626be — awaiting tagged release

https://github.com/notepad-plus-plus/notepad-plus-plus/commit/046af3f626be7715886412313fc18f58b30dfcaf
github Patch Available🟡 PoC Available

Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path · Advisory · notepad-plus-plus/notepad-plus-plus · GitHub

Affected: 8.9.7) — but in a

https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-pxgg-96p2-c3hx

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 24× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-03 21:58 UTCEG score recompute
  2. 2026-10-02 21:14 UTCEG score recompute
  3. 2026-10-02 17:57 UTCEPSS rescore
  4. 2026-10-01 20:31 UTCEG score recompute
  5. 2026-10-01 19:50 UTCEPSS rescore
  6. 2026-09-30 19:52 UTCEG score recompute
  7. 2026-09-30 15:04 UTCEPSS rescore
  8. 2026-09-29 19:15 UTCEG score recompute
  9. 2026-09-29 06:41 UTCEG score recompute
  10. 2026-09-28 18:22 UTCEG score recompute
  11. 2026-09-28 17:53 UTCEG score recompute
  12. 2026-09-28 13:52 UTCEPSS rescore
  13. 2026-09-27 21:40 UTCEG score recompute
  14. 2026-09-27 13:48 UTCEPSS rescore
  15. 2026-09-26 21:02 UTCEG score recompute
  16. 2026-09-26 15:59 UTCEPSS rescore
  17. 2026-09-26 08:41 UTCEG score recompute
  18. 2026-09-24 19:15 UTCEG score recompute
  19. 2026-09-24 14:04 UTCEPSS rescore
  20. 2026-09-23 18:37 UTCEG score recompute
  21. 2026-09-23 17:54 UTCEPSS rescore
  22. 2026-09-22 18:32 UTCEG score recompute
  23. 2026-09-22 17:25 UTCEG score recompute
  24. 2026-09-22 17:23 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-86054?
CVE-2026-86054 is a high vulnerability published on September 22, 2026. 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[MAXPATH] with unbounded wcscpy and…
When was CVE-2026-86054 disclosed?
CVE-2026-86054 was first published on September 22, 2026, with the most recent update on September 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-86054 actively exploited?
CVE-2026-86054 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (12th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-86054?
CVE-2026-86054 has a CVSS base score of 7.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-86054?
A fix for CVE-2026-86054 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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