CVE-2026-74599

CVE CVE-2026-74599EUVD EUVD-2026-64536Published 2026-08-22T15:31:48.000ZLast changed 2026-08-23T12:47:39.000Z

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: mm/ptdump: always stabilise against page table freeing using init_mm Previous commits have established the invariant that kernel page table freeing is performed while an mmap read lock on init_mm is held, which fixes races between ptdump and kernel page table freeing over init_mm. However, x86 and arm64 can perform a ptdump over an mm other than init_mm via ptdump_walk_pgd() and since kernel memory ranges are shared across non-kernel mm's, this means that the race still exists for these cases. Fix this by acquiring a nested mmap write lock for init_mm in ptdump_walk_pgd(). This is safe as we take this after mmap write locking the mm, and nothing acquires the init_mm lock first before locking an arbitrary mm, so no deadlock is possible. Also update walk_page_range_debug() to assert that init_mm is write locked, add a comment explaining why and remove some redundant code, and eliminate the unnecessary and confusing invocation of walk_kernel_page_table_range(). We can safely remove the non-NULL check for walk.mm, as the mmap lock asserts would NULL pointer deref if it was (and of course no callers do this). The first point at which ptdump can race kernel page table freeing is commit b6bdb7517c3d ("mm/vmalloc: add interfaces to free unmapped page table"), so we target this in the Fixes tag.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e <76df4edf7d61ecb711bc517ff4c20a5e85c4e9f7; 4.15.14 <4.16; patch: 6.12.105; b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e <cbd9583bb6f70733d0022a66d3546a15c76ae744; acdb4981644c8e31ccee294bdefff475c0cf587b; 4.9.91 <4.10; patch: 7.1.9; b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e <4adc4c9a9a43d61fe476dfe10811f3df2e7e4106; 0454e2fad9306961540ee7e84da47a8e345b7d22; patch: 5.10.266; b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e <b9c6d048bdfaae78d7d921b454f7de7baefaa2f0; patch: 6.18.45; patch: 0; b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e <3c0391b9a774cc0854f3152e484a9d4835b12b40; 4.4.125 <4.5; 31895cfd79564111cdd5a9f48c5d491ae26a238e; patch: 6.6.153; 4.14.31 <4.15; b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e <27c32e5538344b13c1505a08861e04620c125d47; patch: 5.15.217; 9c7f7bdb1932f8c1e5f80d32c717184701afe701; 4.16; patch: 7.2; b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e <7f740664aec1f832953c2e6d9b8920cd6c8bcc0c

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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