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.
An unprivileged local user can trigger a use-after-free in the kernel, potentially leading to privilege escalation.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| FreeBSD | FreeBSD | unknown |
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Project Subscriptions
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Advisories
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Fixes
Solution
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Workaround
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References
History
Wed, 19 Aug 2026 07:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | Use-after-free in kqueue copy-on-fork | |
| Weaknesses | CWE-416 | |
| References |
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Projects
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MITRE
Status: PUBLISHED
Assigner: freebsd
Published:
Updated: 2026-08-19T07:33:21.096Z
Reserved: 2026-06-29T01:40:17.498Z
Link: CVE-2026-58083
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-19T08:17:12.470
Modified: 2026-08-19T08:17:12.470
Link: CVE-2026-58083
Redhat
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OpenCVE Enrichment
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Weaknesses