{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31774", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.140Z", "datePublished": "2026-05-01T14:15:02.903Z", "dateUpdated": "2026-08-05T12:25:06.767Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:25:06.767Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "io_uring/net.c" ], "versions": [ { "version": "a05d1f625c7aa681d8816bc0f10089289ad07aad", "lessThan": "90ced24c500ad4e129e9e34b7e56fd7849e350b6", "status": "affected", "versionType": "git" }, { "version": "a05d1f625c7aa681d8816bc0f10089289ad07aad", "lessThan": "c314b405dcc4d8b9041124f928f81715d6328bec", "status": "affected", "versionType": "git" }, { "version": "a05d1f625c7aa681d8816bc0f10089289ad07aad", "lessThan": "1b655cd311344117d3052f6552cb20d9901c9d7c", "status": "affected", "versionType": "git" }, { "version": "a05d1f625c7aa681d8816bc0f10089289ad07aad", "lessThan": "b948f9d5d3057b01188e36664e7c7604d1c8ecb5", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "io_uring/net.c" ], "versions": [ { "version": "6.10", "status": "affected" }, { "version": "0", "lessThan": "6.10", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.81", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.22", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.12", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "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" } ] } ] } ], "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" } ], "title": "io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()", "x_generator": { "engine": "bippy-1.2.0" } } } }