CVE-2025-40199
What it is
In the Linux kernel, the following vulnerability has been resolved: page_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches Helge reported that the introduction of PP_MAGIC_MASK let to crashes on boot on his 32-bit parisc machine. The cause of this is the mask is set too wide, so the page_pool_page_is_pp() incurs false positives which crashes the machine. Just disabling the check in page_pool_is_pp() will lead to the page_pool code itself malfunctioning; so instead of doing this, this patch changes the define for PP_DMA_INDEX_BITS to avoid mistaking arbitrary kernel pointers for page_pool-tagged pages. The fix relies on the kernel pointers that alias with the pp_magic field always being above PAGE_OFFSET. With this assumption, we can use the lowest bit of the value of PAGE_OFFSET as the upper bound of the PP_DMA_INDEX_MASK, which should avoid the false positives. Because we cannot rely on PAGE_OFFSET always being a compile-time constant, nor on it always being >0, we fall back to disabling the dma_index storage when there are not enough bits available. This leaves us in the situation we were in before the patch in the Fixes tag, but only on a subset of architecture configurations. This seems to be the best we can do until the transition to page types in complete for page_pool pages. v2: - Make sure there's at least 8 bits available and that the PAGE_OFFSET bit calculation doesn't wrap
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- No patch or advisory is linked yet. Look at mitigations or restrict exposure.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: none linked yet, which raises it.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Record status
- Deferred
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-40199.md and follow it. Check whether this project is affected by CVE-2025-40199. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
