# CVE-2026-80682: linux: In the Linux kernel, the following vulnerability has been resolved:  riscv/mm: use physical alignment for vmemmap_sta...

CVE-2026-80682 is fixed in linux on 1 platform by DEBIAN-CVE-2026-80682 (version 7.1.8-1), released August 29, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-80682
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0018
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 28, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  riscv/mm: use physical alignment for vmemmap_start_pfn  RISC-V computes vmemmap_start_pfn by rounding phys_ram_base down to VMEMMAP_ADDR_ALIGN.  That alignment must therefore be expressed in the physical-address domain.  Commit 476849b0fba4 ("riscv/mm: align vmemmap to maximal folio size") attempted to account for the maximal folio alignment by feeding MAX_FOLIO_VMEMMAP_ALIGN directly into VMEMMAP_ADDR_ALIGN.  However, MAX_FOLIO_VMEMMAP_ALIGN is measured in bytes of struct page storage, whereas VMEMMAP_ADDR_ALIGN is used to align a physical address.  The mask-based compound_info encoding requires pfn_to_page(0) to be naturally aligned to MAX_FOLIO_VMEMMAP_ALIGN.  Commit 9f94db4c7eaa ("mm/sparse: check memmap alignment for compound_info_has_mask()") added a check for that requirement and exposed the unit mismatch on systems such as QEMU virt, where the DRAM base is not aligned to MAX_FOLIO_NR_PAGES * PAGE_SIZE.  Here is the log: [    0.000000][    C0] ------------[ cut here ]------------ [    0.000000][    C0] WARNING: mm/sparse.c:365 at sparse_init+0x58a/0x6fe, CPU#0: swapper/0 [    0.000000][    C0] Modules linked in: [    0.000000][    C0] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.2.0-rc3-g1d8304bdd65f #2 PREEMPT  [    0.000000][    C0] Hardware name: riscv-virtio,qemu (DT) [    0.000000][    C0] epc : sparse_init+0x58a/0x6fe [    0.000000][    C0]  ra : sparse_init+0x58a/0x6fe [    0.000000][    C0] epc : ffffffff86851c88 ra : ffffffff86851c88 sp : ffffffff88807a30 [    0.000000][    C0]  gp : ffffffff8a3bf240 tp : ffffffff88842080 t0 : ff600000ffab6000 [    0.000000][    C0]  t1 : 000000017fab6000 t2 : 65203a6573726363 s0 : ffffffff88807bc0 [    0.000000][    C0]  s1 : 000000000e000000 a0 : 0000000000000007 a1 : 0000000000000000 [    0.000000][    C0]  a2 : 0000000000000002 a3 : ffffffff86851c88 a4 : 0000000000000000 [    0.000000][    C0]  a5 : ffffffff88843080 a6 : 0000000000000003 a7 : 0000000000000000 [    0.000000][    C0]  s2 : ff60000000000000 s3 : 0040000000000000 s4 : 0004000000000000 [    0.000000][    C0]  s5 : ffffffff8a4d92e0 s6 : ff600000ffab55e0 s7 : ffffffff88384d00 [    0.000000][    C0]  s8 : 0000000000000003 s9 : ffffffff88384cc1 s10: ffffffff88384cc0 [    0.000000][    C0]  s11: ffffffff8a4daae0 t3 : ffffffff915e8b20 t4 : ffffffff915e8b20 [    0.000000][    C0]  t5 : ffffffff915e8b20 t6 : ffffffff915e8bc8 ssp : 0000000000000000 [    0.000000][    C0] status: 0000000200000100 badaddr: ffffffff86851c88 cause: 0000000000000003 [    0.000000][    C0] [<ffffffff86851c88>] sparse_init+0x58a/0x6fe [    0.000000][    C0] [<ffffffff8683d396>] mm_core_init_early+0x116/0x1e30 [    0.000000][    C0] [<ffffffff86801edc>] start_kernel+0xd2/0x848  Convert MAX_FOLIO_VMEMMAP_ALIGN to the equivalent physical alignment before using it in VMEMMAP_ADDR_ALIGN.  This keeps the existing round_down() logic while making the resulting vmemmap base satisfy the mask-alignment requirement.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.1.8-1 | [DEBIAN-CVE-2026-80682](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80682.md) | Aug 29, 2026 |

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