{"id":"CVE-2026-80810","state":"PUBLISHED","title":"io_uring/rsrc: fix folio size overflow in io_vec_fill_bvec()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/rsrc: fix folio size overflow in io_vec_fill_bvec()\n\nio_vec_fill_bvec() computes the folio size with a plain int 1:\n\n\tunsigned long folio_size = 1 << imu->folio_shift;\n\nimu->folio_shift is unsigned int and comes from folio_shift() of the\nfolio backing the registered buffer, so it can be 32 or more on a 64 bit\nkernel. Shifting int 1 that far is undefined, and on x86 and arm64 the\ncount is taken modulo 32, so a shift of 34 yields 4 rather than 16G.\nEvery other folio_shift shift in this file already uses 1UL.\n\nThe result is that the segment estimate and the fill loop disagree.\nio_estimate_bvec_size() sizes the bvec array with the real shift:\n\n\tmax_segs += (iov[i].iov_len >> shift) + 2;\n\nso a 1M iovec on a 16G folio is charged 2 segments, while\nio_vec_fill_bvec() then walks the same iovec in folio_size chunks of 4\nbytes and writes res_bvec[bvec_idx] a quarter of a million times, past\nthe end of the array it was given. src_bvec is advanced once per\niteration as well, so imu->bvec is read past its end at the same time.\nvalidate_fixed_range() only checks that the range is inside the\nregistered buffer and does not bound the segment count.\n\nReaching it needs a folio with a shift of at least 32, which means a\ngigantic hugetlb page: 16G on arm64 with 64K pages, where\nCONT_PMD_SHIFT is 34 and hugetlb_add_hstate(CONT_PMD_SHIFT - PAGE_SHIFT)\nregisters that size, and likewise on powerpc. x86_64 tops out at 1G, so\na shift of 30, which still fits in int and is unaffected.\n\nUse 1UL, as the rest of the file does.","publishedAt":"2026-09-04T15:13:30.800Z","updatedAt":"2026-10-19T08:44:03.724Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9ef4cbbcb4ac3786a1a4164507511b76b2a572c5","status":"affected","lessThan":"45c945107e007b1fb73e21cd220277652a45521a","versionType":"git"},{"version":"9ef4cbbcb4ac3786a1a4164507511b76b2a572c5","status":"affected","lessThan":"6b308c37fbeba3aa8c634fb1ed53e2f63a5d5a5c","versionType":"git"},{"version":"9ef4cbbcb4ac3786a1a4164507511b76b2a572c5","status":"affected","lessThan":"3267d7c8ba51642117f7bdd1ece02b2540668476","versionType":"git"},{"version":"9ef4cbbcb4ac3786a1a4164507511b76b2a572c5","status":"affected","lessThan":"3f3a6a16bbe8bde76532d9415438f8cdef439e5d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/rsrc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.18.47","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.11","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2.1","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/rsrc.c"]}],"references":["https://git.kernel.org/stable/c/45c945107e007b1fb73e21cd220277652a45521a","https://git.kernel.org/stable/c/6b308c37fbeba3aa8c634fb1ed53e2f63a5d5a5c","https://git.kernel.org/stable/c/3267d7c8ba51642117f7bdd1ece02b2540668476","https://git.kernel.org/stable/c/3f3a6a16bbe8bde76532d9415438f8cdef439e5d"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/80xxx/CVE-2026-80810.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80810","state":"PUBLISHED","datePublished":"2026-09-04T15:13:30.800Z","dateUpdated":"2026-10-19T08:44:03.724Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-26T14:34:25.794Z"},"containers":{"cna":{"title":"io_uring/rsrc: fix folio size overflow in io_vec_fill_bvec()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/rsrc: fix folio size overflow in io_vec_fill_bvec()\n\nio_vec_fill_bvec() computes the folio size with a plain int 1:\n\n\tunsigned long folio_size = 1 << imu->folio_shift;\n\nimu->folio_shift is unsigned int and comes from folio_shift() of the\nfolio backing the registered buffer, so it can be 32 or more on a 64 bit\nkernel. Shifting int 1 that far is undefined, and on x86 and arm64 the\ncount is taken modulo 32, so a shift of 34 yields 4 rather than 16G.\nEvery other folio_shift shift in this file already uses 1UL.\n\nThe result is that the segment estimate and the fill loop disagree.\nio_estimate_bvec_size() sizes the bvec array with the real shift:\n\n\tmax_segs += (iov[i].iov_len >> shift) + 2;\n\nso a 1M iovec on a 16G folio is charged 2 segments, while\nio_vec_fill_bvec() then walks the same iovec in folio_size chunks of 4\nbytes and writes res_bvec[bvec_idx] a quarter of a million times, past\nthe end of the array it was given. src_bvec is advanced once per\niteration as well, so imu->bvec is read past its end at the same time.\nvalidate_fixed_range() only checks that the range is inside the\nregistered buffer and does not bound the segment count.\n\nReaching it needs a folio with a shift of at least 32, which means a\ngigantic hugetlb page: 16G on arm64 with 64K pages, where\nCONT_PMD_SHIFT is 34 and hugetlb_add_hstate(CONT_PMD_SHIFT - PAGE_SHIFT)\nregisters that size, and likewise on powerpc. x86_64 tops out at 1G, so\na shift of 30, which still fits in int and is unaffected.\n\nUse 1UL, as the rest of the file does."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9ef4cbbcb4ac3786a1a4164507511b76b2a572c5","status":"affected","lessThan":"45c945107e007b1fb73e21cd220277652a45521a","versionType":"git"},{"version":"9ef4cbbcb4ac3786a1a4164507511b76b2a572c5","status":"affected","lessThan":"6b308c37fbeba3aa8c634fb1ed53e2f63a5d5a5c","versionType":"git"},{"version":"9ef4cbbcb4ac3786a1a4164507511b76b2a572c5","status":"affected","lessThan":"3267d7c8ba51642117f7bdd1ece02b2540668476","versionType":"git"},{"version":"9ef4cbbcb4ac3786a1a4164507511b76b2a572c5","status":"affected","lessThan":"3f3a6a16bbe8bde76532d9415438f8cdef439e5d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/rsrc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.18.47","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.11","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2.1","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/rsrc.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/45c945107e007b1fb73e21cd220277652a45521a"},{"url":"https://git.kernel.org/stable/c/6b308c37fbeba3aa8c634fb1ed53e2f63a5d5a5c"},{"url":"https://git.kernel.org/stable/c/3267d7c8ba51642117f7bdd1ece02b2540668476"},{"url":"https://git.kernel.org/stable/c/3f3a6a16bbe8bde76532d9415438f8cdef439e5d"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:44:03.724Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.18.47"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.1.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.2.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}