Code execution via malformed UTF-16 file conversion
Published Aug 25, 2023 · Updated Oct 2, 2024
Heap buffer overflow in Notepad++ 8.5.6 and earlier allows attackers to execute arbitrary code by opening a crafted UTF-16 file. Utf8_16_Read::convert underallocates its output buffer for malformed odd-length input, consumes an extra byte, and writes three bytes past the heap allocation. Exploitation requires a user to open the file; the published PoC demonstrates the out-of-bounds write rather than code execution.
Summary
What happened
Heap buffer overflow in Notepad++ 8.5.6 and earlier allows attackers to execute arbitrary code by opening a crafted UTF-16 file. Utf8_16_Read::convert underallocates its output buffer for malformed odd-length input, consumes an extra byte, and writes three bytes past the heap allocation. Exploitation requires a user to open the file; the published PoC demonstrates the out-of-bounds write rather than code execution.
The record
- CVE
- CVE-2023-40031
- Published
- Aug 25, 2023
- Updated
- Oct 2, 2024
- Vendor
- Notepad++
- Product
- Notepad++
- Classifications
- CWE-122, CWE-120, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 25, 2023CVE publishedPublication date reported by the CVE source.
- Oct 2, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=<= 8.5.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GitHub Security Lab crafted UTF-16 file PoCproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo