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VulnerabilityPublished Updated

CVE-2026-58100: FreeBSD · Race Condition

Affects FreeBSDSource CVE Database V5

0

Not known to be exploited · CVSS 7.0 High : upgrade to p4 soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
7.0High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in p4
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade FreeBSD to p4.

Affected software

ProductAffectedFixed in
FreeBSDFreeBSDAffected
  • >=15.1-RELEASE <p4
Fixed in
  • p4

AI-suggested

A fix for this vulnerability is available in FreeBSD patch level p4. Users should upgrade to p4 or later to remediate this issue. Since the vendor advisory confirms the fixed version, applying this official fix is the recommended mitigation.

Description

CVE-2026-58100 is a race condition vulnerability in FreeBSD's kqueue_fork_copy_knote() function. It occurs because the function indexes the child's file descriptor table using a knote's file descriptor number without performing bounds checking. This can lead to an out-of-bounds read if a concurrent thread in the parent process grows the parent's file descriptor table and registers knotes with file descriptor numbers beyond the child's table size. An unprivileged local user may exploit this race condition to escalate privileges.

References

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