{"id":"CVE-2026-31774","state":"PUBLISHED","title":"io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()\n\nsqe->len is __u32 but gets stored into sr->len which is int. When\nuserspace passes sqe->len values exceeding INT_MAX (e.g. 0xFFFFFFFF),\nsr->len overflows to a negative value. This negative value propagates\nthrough the bundle recv/send path:\n\n  1. io_recv(): sel.val = sr->len (ssize_t gets -1)\n  2. io_recv_buf_select(): arg.max_len = sel->val (size_t gets\n     0xFFFFFFFFFFFFFFFF)\n  3. io_ring_buffers_peek(): buf->len is not clamped because max_len\n     is astronomically large\n  4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs()\n  5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1,\n     causing ret to increase instead of decrease, creating an\n     infinite loop that reads past the allocated iov[] array\n\nThis results in a slab-out-of-bounds read in io_bundle_nbufs() from\nthe kmalloc-64 slab, as nbufs increments past the allocated iovec\nentries.\n\n  BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160\n  Read of size 8 at addr ffff888100ae05c8 by task exp/145\n  Call Trace:\n   io_bundle_nbufs+0x128/0x160\n   io_recv_finish+0x117/0xe20\n   io_recv+0x2db/0x1160\n\nFix this by rejecting negative sr->len values early in both\nio_sendmsg_prep() and io_recvmsg_prep(). Since sqe->len is __u32,\nany value > INT_MAX indicates overflow and is not a valid length.","publishedAt":"2026-05-01T14:15:02.903Z","updatedAt":"2026-10-19T19:06:08.469Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a05d1f625c7aa681d8816bc0f10089289ad07aad","status":"affected","lessThan":"90ced24c500ad4e129e9e34b7e56fd7849e350b6","versionType":"git"},{"version":"a05d1f625c7aa681d8816bc0f10089289ad07aad","status":"affected","lessThan":"c314b405dcc4d8b9041124f928f81715d6328bec","versionType":"git"},{"version":"a05d1f625c7aa681d8816bc0f10089289ad07aad","status":"affected","lessThan":"1b655cd311344117d3052f6552cb20d9901c9d7c","versionType":"git"},{"version":"a05d1f625c7aa681d8816bc0f10089289ad07aad","status":"affected","lessThan":"b948f9d5d3057b01188e36664e7c7604d1c8ecb5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/net.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.81","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.22","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.12","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/net.c"]}],"references":["https://git.kernel.org/stable/c/90ced24c500ad4e129e9e34b7e56fd7849e350b6","https://git.kernel.org/stable/c/c314b405dcc4d8b9041124f928f81715d6328bec","https://git.kernel.org/stable/c/1b655cd311344117d3052f6552cb20d9901c9d7c","https://git.kernel.org/stable/c/b948f9d5d3057b01188e36664e7c7604d1c8ecb5"],"weaknesses":["CWE-190"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31774.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31774","state":"PUBLISHED","datePublished":"2026-05-01T14:15:02.903Z","dateUpdated":"2026-10-19T19:06:08.469Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.140Z"},"containers":{"cna":{"title":"io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()\n\nsqe->len is __u32 but gets stored into sr->len which is int. When\nuserspace passes sqe->len values exceeding INT_MAX (e.g. 0xFFFFFFFF),\nsr->len overflows to a negative value. This negative value propagates\nthrough the bundle recv/send path:\n\n  1. io_recv(): sel.val = sr->len (ssize_t gets -1)\n  2. io_recv_buf_select(): arg.max_len = sel->val (size_t gets\n     0xFFFFFFFFFFFFFFFF)\n  3. io_ring_buffers_peek(): buf->len is not clamped because max_len\n     is astronomically large\n  4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs()\n  5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1,\n     causing ret to increase instead of decrease, creating an\n     infinite loop that reads past the allocated iov[] array\n\nThis results in a slab-out-of-bounds read in io_bundle_nbufs() from\nthe kmalloc-64 slab, as nbufs increments past the allocated iovec\nentries.\n\n  BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160\n  Read of size 8 at addr ffff888100ae05c8 by task exp/145\n  Call Trace:\n   io_bundle_nbufs+0x128/0x160\n   io_recv_finish+0x117/0xe20\n   io_recv+0x2db/0x1160\n\nFix this by rejecting negative sr->len values early in both\nio_sendmsg_prep() and io_recvmsg_prep(). Since sqe->len is __u32,\nany value > INT_MAX indicates overflow and is not a valid length."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a05d1f625c7aa681d8816bc0f10089289ad07aad","status":"affected","lessThan":"90ced24c500ad4e129e9e34b7e56fd7849e350b6","versionType":"git"},{"version":"a05d1f625c7aa681d8816bc0f10089289ad07aad","status":"affected","lessThan":"c314b405dcc4d8b9041124f928f81715d6328bec","versionType":"git"},{"version":"a05d1f625c7aa681d8816bc0f10089289ad07aad","status":"affected","lessThan":"1b655cd311344117d3052f6552cb20d9901c9d7c","versionType":"git"},{"version":"a05d1f625c7aa681d8816bc0f10089289ad07aad","status":"affected","lessThan":"b948f9d5d3057b01188e36664e7c7604d1c8ecb5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/net.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.81","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.22","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.12","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/net.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/90ced24c500ad4e129e9e34b7e56fd7849e350b6"},{"url":"https://git.kernel.org/stable/c/c314b405dcc4d8b9041124f928f81715d6328bec"},{"url":"https://git.kernel.org/stable/c/1b655cd311344117d3052f6552cb20d9901c9d7c"},{"url":"https://git.kernel.org/stable/c/b948f9d5d3057b01188e36664e7c7604d1c8ecb5"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable path is reached through local io_uring syscalls by submitting IORING_OP_RECV/SEND with provided buffer selection and bundle flags.\nAC:L - An attacker controls the SQE length, buffer ring contents, and socket traffic needed to trigger the slab out-of-bounds read; no race or external condition is required.\nPR:L - A basic unprivileged local user can normally create an io_uring instance and use ordinary sockets and provided buffer rings, absent non-default sysctl/LSM restrictions.\nUI:N - No victim action is needed after the attacker has local execution; the attacker submits the crafted io_uring operations directly.\nS:U - The impact remains within the local kernel/host security authority and does not cross a VM, IOMMU, or separate security-scope boundary.\nC:H - The bug causes an unbounded slab out-of-bounds read of iovec entries from kernel heap memory, and it is not strictly limited to a small fixed disclosure surface.\nI:N - The immediate primitive is an out-of-bounds read used for buffer accounting, with no demonstrated arbitrary kernel write or control-flow modification.\nA:H - The out-of-bounds read can trigger a KASAN/oops crash or an unbounded loop/page fault in kernel context, causing high availability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:25:06.767Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.81"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.18.22"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.19.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-31774","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:13:11.625324Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-190","lang":"en","type":"CWE","description":"CWE-190 Integer Overflow or Wraparound"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:06:08.469Z"}}]}}}