Local privilege escalation via unchecked syscall index
Published May 21, 2026 · Updated May 21, 2026
Out-of-bounds kernel access in FreeBSD allows local users to gain root privileges through a crafted PT_SC_REMOTE request. In ptrace_syscallreq(), the kernel replaces syscall(2) or __syscall(2) with an argument-supplied syscall number, then indexes the sysent table without rechecking its bounds. The attacker must be able to debug a process; 14.3-RELEASE before p14, 14.4-RELEASE before p5, and 15.0-RELEASE before p9 are affected.
Summary
What happened
Out-of-bounds kernel access in FreeBSD allows local users to gain root privileges through a crafted PT_SC_REMOTE request. In ptrace_syscallreq(), the kernel replaces syscall(2) or __syscall(2) with an argument-supplied syscall number, then indexes the sysent table without rechecking its bounds. The attacker must be able to debug a process; 14.3-RELEASE before p14, 14.4-RELEASE before p5, and 15.0-RELEASE before p9 are affected.
The record
- CVE
- CVE-2026-45253
- Published
- May 21, 2026
- Updated
- May 21, 2026
- Vendor
- The FreeBSD Project
- Product
- FreeBSD
- Classifications
- CWE-787, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 21, 2026CVE publishedPublication date reported by the CVE source.
- May 21, 2026Record 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=14.3-RELEASE <p14
- Affected versionversion=14.4-RELEASE <p5
- Affected versionversion=15.0-RELEASE <p9
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.
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