CVE-2026-58099: 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, 17:16 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 is available in FreeBSD patch level p4. Users should upgrade to p4 or later to remediate this vulnerability. No additional mitigation actions are indicated beyond applying the official patch.
Description
CVE-2026-58099 is a race condition vulnerability in FreeBSD affecting the copying of knotes from a parent kqueue to a child. The flaw arises because marker knotes, which track list traversal positions internally, were not properly excluded before being marked as in-flux and releasing the kqueue lock. This can lead to use-after-free conditions if another thread frees a marker while the lock is dropped. An unprivileged local user could exploit this to escalate privileges on the system.