CVE-2026-58083

While the kernel was copying knotes during fork, a knote with a timer-based filter could fire and be enqueued on the kqueue's active list before the copy was complete. The copy routine did not account for this and could enqueue the new knote a second time, corrupting the active list. In addition, the copy routine did not hold the appropriate locks while reading knote state, allowing further races. An unprivileged local user can trigger a use-after-free in the kernel, potentially leading to privilege escalation.

CVSS v3 8.4 HIGH

8.4^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.5 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://security.freebsd.org/advisories/FreeBSD-SA-26:50.kqueue.asc	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:freebsd:freebsd:15.1:-::::::
	cpe:2.3:o:freebsd:freebsd:15.1:p1::::::
	cpe:2.3:o:freebsd:freebsd:15.1:rc2::::::
	cpe:2.3:o:freebsd:freebsd:15.1:rc3-p1::::::

History

27 Oct 2026, 12:10

Type	Values Removed	Values Added
Summary		(es) Mientras el kernel copiaba knotes durante el fork, un knote con un filtro basado en temporizador podría activarse y ser encolado en la lista activa del kqueue antes de que la copia estuviera completa. La rutina de copia no tuvo esto en cuenta y podría encolar el nuevo knote una segunda vez, corrompiendo la lista activa. Además, la rutina de copia no mantenía los bloqueos apropiados mientras leía el estado del knote, permitiendo más condiciones de carrera. Un usuario local sin privilegios puede desencadenar un uso después de liberación en el kernel, lo que podría llevar a una escalada de privilegios.

Information

Published : 2026-08-19 08:17

Updated : 2026-10-27 12:10

NVD link : CVE-2026-58083

Mitre link : CVE-2026-58083

CVE.ORG link : CVE-2026-58083

JSON object : View

Products Affected

freebsd

freebsd

CWE

CWE-416

Use After Free

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