CVE-2026-58100: FreeBSD · Race Condition
Affects FreeBSDSource CVE Database V5
Not known to be exploited · CVSS 7.0 High : upgrade to p4 soon.
Data as of 26 Oct 2026, 14:18 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| FreeBSDFreeBSD | Affected
| Fixed in
|
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.