CVE-2026-89486 ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()
A use-after-free in the Linux kernel IPMI driver allows attackers to potentially execute code or escalate privileges due to missing RCU synchronization.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89486?
CVE-2026-89486 is a high-severity use after free vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()
Commit 9e91f8a6c868 ("ipmi:msghandler: Remove srcu for the ipmi_interfaces list") dropped the synchronize_rcu() between unlinking the command receivers from intf->cmd_rcvrs and freeing them, updating only the comment that explains why the barrier is needed.
The cmd_rcvrs list is still traversed under plain RCU: find_cmd_rcvr() walks it inside rcu_read_lock(), and handle_ipmb_get_msg_cmd() borrows rcvr->user from that lookup within the same read-side section. Without the grace period, _ipmi_destroy_user() can kfree() a cmd_rcvr while a reader still holds a pointer to it, causing a use-after-free.
The rework only made srcu unnecessary for the interfaces list; the cmd_rcvrs list still relies on plain RCU. Restore the synchronize_rcu() before freeing the receivers.
Which versions are affected by CVE-2026-89486?
How do I fix CVE-2026-89486?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-89486 being exploited?
There is no known exploitation of CVE-2026-89486 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-89486, DEBIAN-CVE-2026-89486, GHSA-6jq9-cvjw-v2h5, UBUNTU-CVE-2026-89486.