Vulnerability in Notepad-Plus-Plus Notepad\+\+
CVE-2026-52885
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.
Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H.
EPSS exploit prediction
EPSS: 0.001 (1.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 1.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000
Affected products
- Notepad-Plus-Plus Notepad\+\+
- Notepad-Plus-Plus — versions < 8.9.6.4
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-qm4c-qg… (Exploit, Patch, Vendor Advisory)
- github.com/notepad-plus-plus/notepad-plus-plus/commit/4f7563c7c7f8ffa0d795ec86a… (Patch)
Frequently asked questions
- What is CVE-2026-52885?
- CVE-2026-52885 is a medium-severity vulnerability in Notepad-Plus-Plus Notepad\+\+, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 6.3/10. Published 2026-06-26.
- How severe is CVE-2026-52885?
- Medium severity. CVSS v3 base score is 6.3 out of 10.
- Is CVE-2026-52885 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.