CVE intelligence

CVE-2026-99172

Vulnerability intelligence

Published Oct 28, 2026Sources checked Oct 28, 2026

N/ACVSS not listedScore unavailable

What this means

Review the available evidence

CVE-2026-99172. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 29, 2026

Release Notes

CISA KEVNot listedBased on the latest collected catalog

EPSSUnavailableNo current score collected

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-99172?

In the Linux kernel, the following vulnerability has been resolved:

ipc: drop the mqueue mount with kern_unmount() on setup failure

mq_init_ns() creates the mqueue mount with fc_mount_longterm(), so its ->mnt_ns is MNT_NS_INTERNAL. When setting up the mqueue or ipc sysctls or msg_init_ns() fails afterwards, create_ipc_ns() drops it with a plain mntput().

With ->mnt_ns set that takes the fast path of mntput_no_expire(). The count drops to zero and nothing ever kills the mount, so the mount and the mqueue superblock are leaked.

Commit dc55e35f9e81 ("ipc: Store mqueue sysctls in the ipc namespace") added the first failure path after mq_init_ns() and never dropped the mount. Commit 7229d74e5e8c ("ipc: create_ipc_ns: drop mqueue mount on sysctl setup failure") tried to fix that with a mntput() but that doesn't help for a long-term mount.

Use kern_unmount(). free_ipc() open-codes the same thing for a namespace that made it.

Source: NVD