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Vulnerability record · CVE-2026-52885 · published 26 June 2026

CVE-2026-52885: Notepad-plus-plus notepad\+\+ toctou race condition vulnerability

Notepad Plus Plus · Notepad\+\+

Notepad++ is a free and open-source source code editor. Prior to 8.9.6.4, NppCommands.cpp checks the HMAC of the on-disk shortcuts.xml at the moment a user command fires (Time-of-Check). However, the command payload is taken from the in-memory _userCommands vector, which is populated at application startup and never re-synchronized with the on-disk file (Time-of-Use). Swapping shortcuts.xml between startup and command execution causes the HMAC check to validate a clean file while a malicious command runs. An attacker with write access to shortcuts.xml places a malicious version on disk before launch, then immediately restores the legitimate file. The HMAC check at execution time validates the restored legitimate file (check passes), while the malicious payload executes from memory. This vulnerability is fixed in 8.9.6.4.

7.5 CVSS 4.0 High EPSS 0.13% · top 98.1% CWE-367 · TOCTOU race condition
7.5CVSS 4.0 base score
0.13%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 2 tagged exploit
29 Jun 2026Last modified by NVD

Description

Notepad++ is a free and open-source source code editor. Prior to 8.9.6.4, NppCommands.cpp checks the HMAC of the on-disk shortcuts.xml at the moment a user command fires (Time-of-Check). However, the command payload is taken from the in-memory _userCommands vector, which is populated at application startup and never re-synchronized with the on-disk file (Time-of-Use). Swapping shortcuts.xml between startup and command execution causes the HMAC check to validate a clean file while a malicious command runs. An attacker with write access to shortcuts.xml places a malicious version on disk before launch, then immediately restores the legitimate file. The HMAC check at execution time validates the restored legitimate file (check passes), while the malicious payload executes from memory. This vulnerability is fixed in 8.9.6.4.

CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/notepad-plus-plus/notepad-plus-plus/commit/4f7563c7c7f8ffa0d795ec86a7777067c7d644b5 Patch
https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-qm4c-qg8p-qfcr ExploitPatchVendor Advisory
https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-qm4c-qg8p-qfcr ExploitPatchVendor Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-52885), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.