io_uring/rsrc: fix folio size overflow in io_vec_fill_bvec()
Summary
| CVE | CVE-2026-80810 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-04 16:18:08 UTC |
| Updated | 2026-09-04 16:18:08 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: fix folio size overflow in io_vec_fill_bvec() io_vec_fill_bvec() computes the folio size with a plain int 1: unsigned long folio_size = 1 << imu->folio_shift; imu->folio_shift is unsigned int and comes from folio_shift() of the folio backing the registered buffer, so it can be 32 or more on a 64 bit kernel. Shifting int 1 that far is undefined, and on x86 and arm64 the count is taken modulo 32, so a shift of 34 yields 4 rather than 16G. Every other folio_shift shift in this file already uses 1UL. The result is that the segment estimate and the fill loop disagree. io_estimate_bvec_size() sizes the bvec array with the real shift: max_segs += (iov[i].iov_len >> shift) + 2; so a 1M iovec on a 16G folio is charged 2 segments, while io_vec_fill_bvec() then walks the same iovec in folio_size chunks of 4 bytes and writes res_bvec[bvec_idx] a quarter of a million times, past the end of the array it was given. src_bvec is advanced once per iteration as well, so imu->bvec is read past its end at the same time. validate_fixed_range() only checks that the range is inside the registered buffer and does not bound the segment count. Reaching it needs a folio with a shift of at least 32, which means a gigantic hugetlb page: 16G on arm64 with 64K pages, where CONT_PMD_SHIFT is 34 and hugetlb_add_hstate(CONT_PMD_SHIFT - PAGE_SHIFT) registers that size, and likewise on powerpc. x86_64 tops out at 1G, so a shift of 30, which still fits in int and is unaffected. Use 1UL, as the rest of the file does. |
Risk And Classification
EPSS: 0.001680000 probability, percentile 0.063030000 (date 2026-09-07)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 9ef4cbbcb4ac3786a1a4164507511b76b2a572c5 45c945107e007b1fb73e21cd220277652a45521a git | Not specified |
| CNA | Linux | Linux | affected 9ef4cbbcb4ac3786a1a4164507511b76b2a572c5 6b308c37fbeba3aa8c634fb1ed53e2f63a5d5a5c git | Not specified |
| CNA | Linux | Linux | affected 9ef4cbbcb4ac3786a1a4164507511b76b2a572c5 3267d7c8ba51642117f7bdd1ece02b2540668476 git | Not specified |
| CNA | Linux | Linux | affected 9ef4cbbcb4ac3786a1a4164507511b76b2a572c5 3f3a6a16bbe8bde76532d9415438f8cdef439e5d git | Not specified |
| CNA | Linux | Linux | affected 6.15 | Not specified |
| CNA | Linux | Linux | unaffected 6.15 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.47 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.11 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.1 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3-rc1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/6b308c37fbeba3aa8c634fb1ed53e2f63a5d5a5c | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/45c945107e007b1fb73e21cd220277652a45521a | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/3267d7c8ba51642117f7bdd1ece02b2540668476 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/3f3a6a16bbe8bde76532d9415438f8cdef439e5d | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.