Medium [CVE-2026-64052] Fix null-ptr-deref in bio_integrity_map_user
This medium-severity Red Hat Linux advisory covers CVE-2026-64052 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat package: kernel-rt.
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Summary
In the Linux kernel, the following vulnerability has been resolved: block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user() pin_user_pages_fast() can partially succeed and return the number of pages that were actually pinned. However, the bio_integrity_map_user() does not handle this partial pinning.
This leads to a general protection fault since bvec_from_pages() dereferences an unpinned page address, which is 0. To fix this, add a check to verify that all requested memory is pinned.
If partial pinning occurs, unpin the memory and return -EFAULT.
Kernel Oops: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 UID: 0 PID: 1061 Comm: nvme-passthroug Not tainted 7.0.0-11783-g90957f9314e8-dirty #16 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 RIP: 0010:bio_integrity_map_user.cold+0x1b0/0x9d6 The `bio_integrity_map_user()` function does not correctly handle partially pinned user pages, which can occur when `pin_user_pages_fast()` returns fewer pages than requested.
This oversight leads to a null-pointer dereference when attempting to access an unpinned page address.
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 6 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 · medium-confidence parse· fetched 6 days 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 6 days ago·verify at source
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