Description

In the Linux kernel, the following vulnerability has been resolved:

mm: avoid leaving partial pfn mappings around in error case

As Jann points out, PFN mappings are special, because unlike normal
memory mappings, there is no lifetime information associated with the
mapping - it is just a raw mapping of PFNs with no reference counting of
a 'struct page'.

That's all very much intentional, but it does mean that it's easy to
mess up the cleanup in case of errors. Yes, a failed mmap() will always
eventually clean up any partial mappings, but without any explicit
lifetime in the page table mapping itself, it's very easy to do the
error handling in the wrong order.

In particular, it's easy to mistakenly free the physical backing store
before the page tables are actually cleaned up and (temporarily) have
stale dangling PTE entries.

To make this situation less error-prone, just make sure that any partial
pfn mapping is torn down early, before any other error handling.

Classification

CVE ID: CVE-2024-47674

CVSS Base Severity: MEDIUM

CVSS Base Score: 5.5

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.03% (probability of being exploited)

EPSS Percentile: 6.63% (scored less or equal to compared to others)

EPSS Date: 2025-06-02 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: none

SSVC Technical Impact: partial

SSVC Automatable: false

References

https://nvd.nist.gov/vuln/detail/CVE-2024-47674
https://git.kernel.org/stable/c/3213fdcab961026203dd587a4533600c70b3336b
https://git.kernel.org/stable/c/35770ca6180caa24a2b258c99a87bd437a1ee10f
https://git.kernel.org/stable/c/5b2c8b34f6d76bfbd1dd4936eb8a0fbfb9af3959
https://git.kernel.org/stable/c/65d0db500d7c07f0f76fc24a4d837791c4862cd2
https://git.kernel.org/stable/c/a95a24fcaee1b892e47d5e6dcc403f713874ee80
https://git.kernel.org/stable/c/954fd4c81f22c4b6ba65379a81fd252971bf4ef3
https://git.kernel.org/stable/c/79a61cc3fc0466ad2b7b89618a6157785f0293b3
https://project-zero.issues.chromium.org/issues/366053091

Timeline