Medium [CVE-2026-74514] Fix memory accounting for pinned/unpinned pages
This medium-severity Red Hat Linux advisory covers CVE-2026-74514 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9.
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Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: s390: pci: Fix memory accounting for pinned/unpinned pages The account_mem() and unaccount_mem() functions call get_uid() which increments the reference count of struct user_struct on every invocation. But we don't decrement the count by calling free_uid().
It also accounted/unaccounted the pages against the current->mm. But its possible the unaccount_mem() can be called from a different process context than the one that originally pinned the pages.
Let's fix this by storing the pinning process user_struct and mm_struct when accounting for pinned pages, and subsequently free these resources when the pages are unpinned. [borntraeger@linux.ibm.com: Fixed whitespace] A flaw was found in the KVM (Kernel-based Virtual Machine) s390 PCI component.
Incorrect memory accounting in the `account_mem()` and `unaccount_mem()` functions, specifically related to the handling of pinned and unpinned pages, can lead to a resource leak.
This occurs because the reference count for user structures is not properly decremented, and memory accounting might be performed in a different process context than the one that originally pinned the pages. This issue could potentially lead to resource exhaustion, resulting in a Denial of Service (DoS) for the system.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 1 hour 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 · medium-confidence parse· fetched 1 hour ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
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