CVE-2019-5596 — In FreeBSD 11

In FreeBSD 11.2-STABLE after r338618 and before r343786, 12.0-STABLE before r343781, and 12.0-RELEASE before 12.0-RELEASE-p3, a bug in the reference count implementation for UNIX domain sockets can cause a file structure to be incorrectly released potentially allowing a malicious

01What is this vulnerability?

In FreeBSD 11.2-STABLE after r338618 and before r343786, 12.0-STABLE before r343781, and 12.0-RELEASE before 12.0-RELEASE-p3, a bug in the reference count implementation for UNIX domain sockets can cause a file structure to be incorrectly released potentially allowing a malicious local user to gain root privileges or escape from a jail.

02Affected products

Vendor	Product	Versions
FreeBSD	FreeBSD	FreeBSD 12.0 before 12.0-RELEASE-p3

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-02-12T05:00:00.000Z
• Last modified: 2024-08-04T20:01:51.303Z

09References

• security.FreeBSD.org — https://security.FreeBSD.org/advisories/FreeBSD-SA-19:02.fd.asc
• packetstormsecurity.com — http://packetstormsecurity.com/files/155790/FreeBSD-fd-Privilege-Escalation.html