Memory corruption via miscounted four-byte UTF-8 conversion
Published Dec 31, 2025 · Updated Dec 31, 2025
Out-of-bounds write in The Tcpdump Group libpcap 1.10.0 through 1.10.5 allows local users to corrupt memory during Windows error handling. In fmtutils.c, utf_16le_to_utf_8_truncated() writes four UTF-8 bytes for supplementary characters but subtracts only three from the remaining buffer length, permitting a later write past the buffer. The Windows-only path requires a high-privileged local context and an error message containing a character encoded as four UTF-8 bytes.
Summary
What happened
Out-of-bounds write in The Tcpdump Group libpcap 1.10.0 through 1.10.5 allows local users to corrupt memory during Windows error handling. In fmtutils.c, utf_16le_to_utf_8_truncated() writes four UTF-8 bytes for supplementary characters but subtracts only three from the remaining buffer length, permitting a later write past the buffer. The Windows-only path requires a high-privileged local context and an error message containing a character encoded as four UTF-8 bytes.
The record
- CVE
- CVE-2025-11964
- Published
- Dec 31, 2025
- Updated
- Dec 31, 2025
- Vendor
- The Tcpdump Group
- Product
- libpcap
- Classifications
- CWE-787
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Dec 31, 2025CVE publishedPublication date reported by the CVE source.
- Dec 31, 2025Record 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=1.10.0 <1.10.6
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
No public exploit references are available in this record.
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