CVE-2026-52885
Swapping shortcuts.xml between startup and command execution causes the HMAC check to validate a clean file while a malicious command runs.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.13%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- 7.5 HIGHCVSS: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/M
- EPSS
- 0.13% probability · 3th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-367
- Affected
- notepad-plus-plus/notepad\+\+
- Source
- security-advisories@github.com
References
- https://github.com/notepad-plus-plus/notepad-plus-plus/commit/4f7563c7c7f8ffa0d795ec86a7777067c7d644b5Patch
- https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-qm4c-qg8p-qfcrExploit, Patch, Vendor Advisory
- https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-qm4c-qg8p-qfcrExploit, Patch, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.