Cyber Resilience

CVE-2026-52884

Notepad-Plus-Plus Notepad\+\+ 8.9.6.1

Public PoC
Published
26 June 2026
Modified
29 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0021 11th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-52884 is a high-severity Trailing Dot (CWE-42) vulnerability in Notepad-Plus-Plus Notepad\+\+. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked at the 11th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and AC-3 (Access Enforcement) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Notepad++ is a free and open-source source code editor. In v8.9.6.1, isInTrustedDirectory() does NOT canonicalize the path before checking. It uses a prefix-based check (PathIsPrefix() or equivalent) that matches paths starting with trusted directory strings. A path traversal using ..\..\…

more

after a trusted directory prefix passes the check while resolving to an untrusted location. The CVE-2026-48800 patch adds isInTrustedDirectory() validation in Command::run() (RunDlg.cpp) before calling ShellExecute(). This function checks whether the resolved executable path is under a trusted directory. This vulnerability is fixed in 8.9.6.2.

CWE(s)
CWE-42

Related Threats

MITRE ATT&CK Enterprise Techniques

T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
T1083 File and Directory Discovery Discovery
Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-6539Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-5525Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2023-40036Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2023-40031Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-48800Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2023-40166Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-48778Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2023-40164Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-48770Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2023-47452Same product: Notepad-Plus-Plus Notepad\+\+

Affected Assets

notepad-plus-plus
notepad\+\+
8.9.6.1

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

SI-10 requires validity checks on information inputs such as file paths, directly stopping acceptance of unvalidated trailing-dot names.

AC-3 Access Enforcement partial match

AC-3 enforces access authorizations on file resources, limiting exploitability of any ambiguous path that reaches the enforcement point.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require input validation and path canonicalization that prevent trailing-dot equivalence flaws.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect path-equivalence flaws before release.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate input validation to reject ambiguous path forms.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture can enforce canonicalization and path normalization controls.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require validation of path inputs to prevent traversal via trailing dots.

References