Out-of-bounds Read in Notepad-Plus-Plus Notepad\+\+
CVE-2026-48770
Notepad++ is a free and open-source source code editor. Prior to 8.9.6.1, a local process in the same interactive Windows session can send a malformed WM_COPYDATA message to Notepad++ using the COPYDATA_FULL_CMDLINE path. The handler appears to process COPYDATASTRUCT.lpData as an unbounded NUL-terminated wchar_t* instead of enforcing COPYDATASTRUCT.cbData. This vulnerability is fixed in 8.9.6.1.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.001 (2.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 2.9% 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 < 8.9.6.1
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-r39g-3m… (Exploit, Patch, Mitigation, Vendor Advisory)
- github.com/notepad-plus-plus/notepad-plus-plus/commit/f20a0888a92ce557a339b833c… (Patch)
Frequently asked questions
- What is CVE-2026-48770?
- CVE-2026-48770 is a medium-severity vulnerability in Notepad-Plus-Plus Notepad\+\+, classified under Out-of-bounds Read. CVSS score: 5.0/10. Published 2026-06-26.
- How severe is CVE-2026-48770?
- Medium severity. CVSS v3 base score is 5.0 out of 10.
- Is CVE-2026-48770 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.