A missing release of resources in the illumos name service cache daemon (nscd) allows a local user…

Why it is Yellow

• CVSS 6.8 medium

References

• https://github.com/illumos/illumos-gate/commit/af810a72c09944e884ec695e8dbf1702a4f424ae
• https://illumos.org/issues/18494
• https://illumos.topicbox.com/groups/developer/T3b859664594b7762/cve-2026-104112-to-cve-2026-104117-denial-of-service-and-missing-authorization-in-door-servers

Original description

A missing release of resources in the illumos name service cache daemon (nscd) allows a local user to exhaust kernel memory. The nscd door server procedure, switcher() in usr/src/cmd/nscd/nscd_frontend.c, does not close file descriptors that are passed with a door call but not used by the request, and the main nscd door at /var/run/name_service_door accepts passed descriptors from any user in its zone. Because nscd also runs with an unlimited file descriptor limit, an unprivileged local user, including one in a non-global zone, can repeatedly pass a descriptor to its zone's nscd in a door_call() loop, causing the file descriptor table of nscd to grow without bound in kernel memory. This causes a denial of service of nscd and can render processes in all zones on the host unresponsive. The flaw has existed since 2006 (illumos-gate commit cb5caa98), and affects any illumos distribution prior to illumos-gate commit af810a72.