{"id":"CVE-2025-40199","title":"page_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\npage_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches\n\nHelge reported that the introduction of PP_MAGIC_MASK let to crashes on\nboot on his 32-bit parisc …","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 4f51fb0d257ff4d406ec27966902de075e3b118e < 15b8a5b4cdc16e9a8bb2a548e12a0fd92997605a","Linux >= ee62ce7a1d909ccba0399680a03c2dee83bcae95 < f62934cea32c8f7b11b747975d69bf5afe4264cf","Linux >= ee62ce7a1d909ccba0399680a03c2dee83bcae95 < 95920c2ed02bde551ab654e9749c2ca7bc3100e0","Linux c30ae60f41f9edd6e1b5cad41cf28ce04dae39e4","Linux >= 6.12.34 < 6.12.54","Linux >= 6.15.3 < 6.16","Linux 6.16"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-15T21:57:57.920017Z"},"published":"2025-11-12","updated":"2026-10-15","sourceUpdated":"2026-10-15T22:02:40.424Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-40199","references":[{"url":"https://git.kernel.org/stable/c/15b8a5b4cdc16e9a8bb2a548e12a0fd92997605a"},{"url":"https://git.kernel.org/stable/c/f62934cea32c8f7b11b747975d69bf5afe4264cf"},{"url":"https://git.kernel.org/stable/c/95920c2ed02bde551ab654e9749c2ca7bc3100e0"}],"tags":["cve.org"],"epss":0.00151,"epssPercentile":0.03835,"ingestedAt":"2026-10-15T22:48:25.551Z","slug":"CVE-2025-40199","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\npage_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches\n\nHelge reported that the introduction of PP_MAGIC_MASK let to crashes on\nboot on his 32-bit parisc machine. The cause of this is the mask is set\ntoo wide, so the page_pool_page_is_pp() incurs false positives which\ncrashes the machine.\n\nJust disabling the check in page_pool_is_pp() will lead to the page_pool\ncode itself malfunctioning; so instead of doing this, this patch changes\nthe define for PP_DMA_INDEX_BITS to avoid mistaking arbitrary kernel\npointers for page_pool-tagged pages.\n\nThe fix relies on the kernel pointers that alias with the pp_magic field\nalways being above PAGE_OFFSET. With this assumption, we can use the\nlowest bit of the value of PAGE_OFFSET as the upper bound of the\nPP_DMA_INDEX_MASK, which should avoid the false positives.\n\nBecause we cannot rely on PAGE_OFFSET always being a compile-time\nconstant, nor on it always being >0, we fall back to disabling the\ndma_index storage when there are not enough bits available. This leaves\nus in the situation we were in before the patch in the Fixes tag, but\nonly on a subset of architecture configurations. This seems to be the\nbest we can do until the transition to page types in complete for\npage_pool pages.\n\nv2:\n- Make sure there's at least 8 bits available and that the PAGE_OFFSET\n  bit calculation doesn't wrap\n\n## Affected\n\n- `Linux >= 4f51fb0d257ff4d406ec27966902de075e3b118e < 15b8a5b4cdc16e9a8bb2a548e12a0fd92997605a`\n- `Linux >= ee62ce7a1d909ccba0399680a03c2dee83bcae95 < f62934cea32c8f7b11b747975d69bf5afe4264cf`\n- `Linux >= ee62ce7a1d909ccba0399680a03c2dee83bcae95 < 95920c2ed02bde551ab654e9749c2ca7bc3100e0`\n- `Linux c30ae60f41f9edd6e1b5cad41cf28ce04dae39e4`\n- `Linux >= 6.12.34 < 6.12.54`\n- `Linux >= 6.15.3 < 6.16`\n- `Linux 6.16`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}