Vulnerability · Published Oct 15, 2026 · Assigned by freebsd

CVE-2026-58100Memory safety bugs in kqueue copy-on-fork implementation

High 7.0

In plain English

A high-severity race condition in FreeBSD from FreeBSD. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities).

Severity (CVSS 3.1)7.0High

Exploit odds (30 days)0.1%top 99.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

kqueue_fork_copy_knote() indexed into the child's file descriptor table using a knote's file descriptor number without a bounds check. Because the child's table is copied before knotes are transferred, a concurrent thread in the parent could grow the parent's table and register knotes with file descriptor numbers beyond the end of the child's table, causing an out-of-bounds read. An unprivileged local user may be able to exploit these races to escalate privileges.

Affected products (as reported)

Vendor	Product	Versions
FreeBSD	FreeBSD	15.1-RELEASE – before p4

Weakness: CWE-362, CWE-125 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:65.kqueue.asc vendor-advisory