illumos Door Server zonestatd.c zsd_server improper authorization

Summaryinfo

A vulnerability classified as very critical has been found in illumos. Affected by this issue is the function zsd_server of the file usr/src/cmd/zonestat/zonestatd/zonestatd.c of the component Door Server. Performing a manipulation results in improper authorization. This vulnerability is identified as CVE-2026-104116. The attack is only possible with local access. There is not any exploit available. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability, which was classified as very critical, was found in illumos (version now known). This affects the function zsd_server of the file usr/src/cmd/zonestat/zonestatd/zonestatd.c of the component Door Server. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A missing authorization check in the illumos zones statistics daemon (zonestatd) allows a local user in any zone to disrupt zonestat in other zones and to determine which zones are running. The zonestatd door server procedure, zsd_server() in usr/src/cmd/zonestat/zonestatd/zonestatd.c, handles the ZSD_CMD_NEW_ZONE command, which is intended to be sent by zoneadmd, without checking the caller's credentials. Because the zonestatd door is accessible to all users in every zone, an unprivileged user can send this command with an arbitrary zone ID, causing zonestatd to re-create its door file in that zone, so that new zonestat requests in that zone can fail while the file is replaced. The time taken to handle the command also reveals whether a given zone ID belongs to a running zone. The flaw has existed since 2010 (illumos-gate commit efd4c9b6), and affects any illumos distribution prior to illumos-gate commit 865b58d2.

It is possible to read the advisory at illumos.topicbox.com. This vulnerability is uniquely identified as CVE-2026-104116 since 10/01/2026. The exploitability is told to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/09/2026). The attack technique deployed by this issue is T1548.002 according to MITRE ATT&CK.

It is declared as proof-of-concept.

Applying the patch 865b58d24a0f1a31c838bffc3a7193d3345fe5ba is able to eliminate this problem.

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• illumos

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