Linux Kernel up to 6.18.13/6.19.3 P2PDMA p2pmem_alloc_mmap reference count

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.18.13/6.19.3. Affected by this vulnerability is the function p2pmem_alloc_mmap of the component P2PDMA. Executing a manipulation can lead to reference count. This vulnerability is registered as CVE-2026-46268. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.13/6.19.3. It has been declared as critical. This vulnerability affects the function p2pmem_alloc_mmap of the component P2PDMA. The manipulation with an unknown input leads to a reference count vulnerability. The CWE definition for the vulnerability is CWE-911. The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: PCI/P2PDMA: Fix p2pmem_alloc_mmap() warning condition Commit b7e282378773 has already changed the initial page refcount of p2pdma page from one to zero, however, in p2pmem_alloc_mmap() it uses "VM_WARN_ON_ONCE_PAGE(!page_ref_count(page))" to assert the initial page refcount should not be zero and the following will be reported when CONFIG_DEBUG_VM is enabled: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x380400000 flags: 0x20000000002000(reserved|node=0|zone=4) raw: 0020000000002000 ff1100015e3ab440 0000000000000000 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: VM_WARN_ON_ONCE_PAGE(!page_ref_count(page)) ------------[ cut here ]------------ WARNING: CPU: 5 PID: 449 at drivers/pci/p2pdma.c:240 p2pmem_alloc_mmap+0x83a/0xa60 Fix by using "page_ref_count(page)" as the assertion condition.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-46268 since 05/13/2026. Technical details are known, but there is no available exploit.

Upgrading to version 6.18.14 or 6.19.4 eliminates this vulnerability. Applying the patch eb9aa9f8010465d927864f5a35bdc5604b0ff51a/9b69243983fb2f4d4d1f4ef0989bc1296547dc2c/cb500023a75246f60b79af9f7321d6e75330c5b5 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

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CPE 2.2info

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Entryinfo

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