{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40199", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.178Z", "datePublished": "2025-11-12T21:56:33.510Z", "dateUpdated": "2026-08-05T12:08:28.841Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:28.841Z" }, "descriptions": [ { "lang": "en", "value": "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 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" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The broken `PP_MAGIC_MASK` is evaluated on every page free/alloc check and on every page_pool skb recycle, driven by ordinary local memory and I/O activity rather than by attacker-supplied packet content; an unprivileged local process reliably reaches `free_page_is_bad()`/`napi_pp_put_page()` through normal slab and socket buffer churn. No remote input influences the aliased pointer values, so Local is the accurate vector.\nAC:L - On an affected architecture (32-bit parisc/m68k/nommu targets whose default `PAGE_OFFSET < 0x40000000`) the false positive is deterministic and occurs with no special setup — it fires during boot on stock configuration, and any page-allocation churn reproduces it. No condition beyond the attacker's control is required.\nPR:L - Any unprivileged local user can drive slab page frees and network buffer recycling that funnel pages through `page_pool_page_is_pp()`/`netmem_is_pp()`; no capability, namespace privilege, or root is needed. The condition even manifests spontaneously under the init process during boot.\nUI:N - No victim action is required — the misidentification happens inside the page allocator and skb free paths during normal kernel operation.\nS:U - Both the flawed check and its consequences (page allocator state, page_pool/skb handling) live entirely within the kernel's own security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - A false positive in `netmem_is_pp()` causes `page->mapping` to be reinterpreted as a `struct page_pool *` and dereferenced throughout `page_pool_put_unrefed_netmem()`, giving a type-confusion read primitive over arbitrary kernel memory; `bad_page()` additionally dumps raw `struct page` contents and kernel pointers to the log.\nI:H - The same type confusion lets `page_pool_recycle_in_cache()`/`page_pool_recycle_in_ring()` write netmem values and update counters at offsets from an uncontrolled kernel pointer, and `skb_pp_frag_ref()` performs `atomic_long_inc()` on the `page->private`-aliased `pp_ref_count`, corrupting page-cache metadata — memory corruption leverageable for control-flow hijack.\nA:H - The reported symptom is a machine crash on boot: every affected slab page free triggers a \"BUG: Bad page state ... page_pool leak\" splat and permanently leaks the page, exhausting memory, while the network path oopses on a wild `page_pool` pointer dereference." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/mm.h", "net/core/page_pool.c" ], "versions": [ { "version": "4f51fb0d257ff4d406ec27966902de075e3b118e", "lessThan": "15b8a5b4cdc16e9a8bb2a548e12a0fd92997605a", "status": "affected", "versionType": "git" }, { "version": "ee62ce7a1d909ccba0399680a03c2dee83bcae95", "lessThan": "f62934cea32c8f7b11b747975d69bf5afe4264cf", "status": "affected", "versionType": "git" }, { "version": "ee62ce7a1d909ccba0399680a03c2dee83bcae95", "lessThan": "95920c2ed02bde551ab654e9749c2ca7bc3100e0", "status": "affected", "versionType": "git" }, { "version": "c30ae60f41f9edd6e1b5cad41cf28ce04dae39e4", "status": "affected", "versionType": "git" }, { "version": "6.12.34", "lessThan": "6.12.54", "status": "affected", "versionType": "semver" }, { "version": "6.15.3", "lessThan": "6.16", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/mm.h", "net/core/page_pool.c" ], "versions": [ { "version": "6.16", "status": "affected" }, { "version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.54", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.4", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.34", "versionEndExcluding": "6.12.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "6.17.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "6.18" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15.3" } ] } ] } ], "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" } ], "title": "page_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches", "x_generator": { "engine": "bippy-1.2.0" } } } }