High [CVE-2026-72042] Fix user refcount underflow in event delivery
This high-severity Red Hat Linux advisory covers CVE-2026-72042.
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Summary
In the Linux kernel, the following vulnerability has been resolved: ipmi: Fix user refcount underflow in event delivery ipmi_alloc_recv_msg(user) takes the temporary user reference owned by the receive message, and ipmi_free_recv_msg() drops it again.
If event delivery fails after allocating receive messages for earlier users, handle_read_event_rsp() rolls those messages back with ipmi_free_recv_msg(). That rollback path still drops user->refcount explicitly after freeing each message.
The extra put can free a user that remains linked on intf->users, so later event delivery may dereference a freed user or trip refcount_t's addition-on-zero warning when ipmi_alloc_recv_msg() tries to acquire another reference. Remove the stale explicit put and the now-dead user assignment.
Keep the list_del() and ipmi_free_recv_msg() calls; they are the required rollback operations. A flaw was found in the Linux kernel's Intelligent Platform Management Interface (IPMI) subsystem.
An issue in the event delivery mechanism, specifically a reference count underflow, can lead to a use-after-free vulnerability. This occurs when a user's reference count is prematurely decremented during event delivery rollback, allowing for the potential dereferencing of freed memory.
This could result in system instability or a denial of service.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 24 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 24 days ago·verify at source
Mitigation checklist
- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Official advisory · high-confidence parse· fetched 24 days ago·verify at source
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