CVE-2026-72043

CVE CVE-2026-72043EUVD EUVD-2026-59001Veröffentlicht 2026-08-15T05:52:02.000ZZuletzt geändert 2026-08-17T05:39:42.000ZCVSS 7.1

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: LoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotect() When hardware page table walker (PTW) is enabled on LoongArch, the CPU may set _PAGE_DIRTY directly in the page table entry during a write TLB miss, without going through the software TLB store handler. The software TLB store handler (tlbex.S:254) sets both _PAGE_DIRTY and_PAGE_MODIFIED together: ori t0, t0, (_PAGE_VALID | _PAGE_DIRTY | _PAGE_MODIFIED) Since hardware PTW only sets _PAGE_DIRTY, the software-only bit, i.e. _PAGE_MODIFIED is left unchanged. This creates a window where a PTE has _PAGE_DIRTY set (hardware knows the page is dirty) but _PAGE_MODIFIED clear (software is unaware). When fork()/clone() triggers copy-on-write, __copy_present_ptes() calls pte_wrprotect(), which unconditionally clears both the _PAGE_WRITE and _PAGE_DIRTY bits: pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_DIRTY); Since _PAGE_MODIFIED was never set, the dirtiness information is lost completely. Subsequently, when memory pressure triggers page reclaim, page_mkclean() / try_to_unmap() sees the page as clean (i.e. pte_dirty() returns false) and the page may be freed without writeback, causing data corruption. Fix this by propagating the _PAGE_DIRTY bit to the _PAGE_MODIFIED bit in both pte_wrprotect() and pmd_wrprotect() before clearing writeable bits: if (pte_val(pte) & _PAGE_DIRTY) pte_val(pte) |= _PAGE_MODIFIED; The pmd_wrprotect() fix handles the CONFIG_TRANSPARENT_HUGEPAGE case, where pmd entries need the same treatment. This ensures the software dirty tracking bit (checked by pte_dirty() and pmd_dirty(), which read both the _PAGE_DIRTY and _PAGE_MODIFIED bits) is preserved across fork COW write-protection. The issue was found by the LTP madvise09 test case, which exercises page reclaim after "madvise(MADV_FREE), write and fork" operation sequence on private anonymous mappings.

Quelle: EUVD (ENISA), im Wortlaut der Meldung.

Produkte, die das Advisory nennt

Diese Angaben stammen aus der Meldung selbst, nicht aus einer Prüfung durch uns.

• Linux — Linux patch: 6.1.178; patch: 7.1.5; 09cfefb7fa70c3af011b0db0a513fd80b2f18abc <76f88650763a35cbf1384c65d66d096fa31cc58d; patch: 0; patch: 6.12.97; 09cfefb7fa70c3af011b0db0a513fd80b2f18abc <018e9828eb523c638fa3d9bdf0fd4956b74555b2; 5.19; patch: 7.2; 09cfefb7fa70c3af011b0db0a513fd80b2f18abc <e483da960892c41fa7f0cf0d2fc2410d65a483d6; patch: 6.18.40; 09cfefb7fa70c3af011b0db0a513fd80b2f18abc <a65f49b6f7ece756394f8f0e85570020e7fd0e35; 09cfefb7fa70c3af011b0db0a513fd80b2f18abc <39bb21a4bff0d70058bf752d7b5aa2e2ccc864a9; patch: 6.6.145; 09cfefb7fa70c3af011b0db0a513fd80b2f18abc <e8a916579e427af32f2de8213dfa23c5df6e6664

Die genannten Versionen sind die Angabe der Meldung. Patchlage vergleicht keine Versionsnummern und leitet aus ihnen keine Aussage ab — welche Version installiert ist, muss ein Mensch nachsehen.

Im Produktkatalog geführt

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• Linux — Linux

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