CVE-2026-58093 — Kernel use-after-free via tty ioctls
The TIOCSCTTY ioctl handler drops the tty lock in order to acquire the process tree lock. After reacquiring the tty lock, the handler did not revalidate the state of the terminal, and could proceed to link a terminal that was concurrently being destroyed to the calling process' session. An unprivileged local user can exploit this race condition to escalate privileges.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Freebsd Freebsd).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (logic error), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Freebsd | Freebsd |
version 15.0-p2version 15.1-p2version 15.1-p1version 15.0-p9version 15.0-p8version 15.0-p7version 15.0-p6version 15.0-p5 and 14 moreversion 15.0-p4version 15.0-p3version 14.4-p1version 15.0-p12version 15.0-p11version 15.0-p10version 15.0-p1version 14.4-p8version 14.4-p7version 14.4-p6version 14.4-p5version 14.4-p4version 14.4-p3version 14.4-p2 |
Vulnerable | NIST National Vulnerability Database |
| Freebsd | Freebsd | ≥ 14.4-RELEASE and < p9≥ 15.0-RELEASE and < p13≥ 15.1-RELEASE and < p3 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.0 | CVSS 3.1 | High | 1.0 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 7.0 | CVSS 3.1 | High | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · freebsd/freebsd
- SSVC assessment updated
- Record published
- CVSS changed · 7.0
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-101309 Multiple vulnerabilities in bhyve device models 19h
- High CVE-2026-101310 Multiple vulnerabilities in bhyve device models 19h
- High CVE-2026-101311 Multiple vulnerabilities in bhyve device models 19h
- Unknown CVE-2026-58099 Memory safety bugs in kqueue copy-on-fork implementation 20h
- Unknown CVE-2026-58100 Memory safety bugs in kqueue copy-on-fork implementation 20h
- Unknown CVE-2026-58098 Heap out-of-bounds access in semop(2) 20h
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-58093 is "Kernel use-after-free via tty ioctls", rated High. It affects Freebsd (Freebsd); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.0 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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