Bug 2502517 (CVE-2026-64052)

Summary: CVE-2026-64052 kernel: block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's bio-integrity module. 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. A local user could exploit this vulnerability to trigger a general protection fault, resulting in a system crash and a denial of service.
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Description OSIDB Bzimport 2026-07-19 17:03:42 UTC 
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
Comment 1 TEJ RATHI 2026-07-20 13:22:38 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026071908-CVE-2026-64052-452e@gregkh/T