{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74256", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.876Z", "datePublished": "2026-08-15T05:57:34.956Z", "dateUpdated": "2026-08-17T05:45:05.356Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:45:05.356Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check\n\nstart and len are u32, so\n\n\tu64 last = start + len;\n\nevaluates start + len in 32-bit and wraps before storing it in last.\nThe bounds check\n\n\tif (start >= offset + l || last > msg->sg.size)\n\t\treturn -EINVAL;\n\ncan then be passed with an out-of-range start/len, after which the pop\nloop runs off the end of the scatterlist and sk_msg_shift_left() calls\nput_page() on the empty msg->sg.end slot:\n\n Oops: general protection fault, probably for non-canonical address\n 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI\n KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]\n RIP: 0010:sk_msg_shift_left net/core/filter.c:2957 [inline]\n RIP: 0010:____bpf_msg_pop_data net/core/filter.c:3103 [inline]\n RIP: 0010:bpf_msg_pop_data+0x753/0x1a10 net/core/filter.c:2984\n Call Trace:\n \n bpf_prog_4cc92c278f4d5d56+0x1b1/0x1e8\n bpf_prog_run_pin_on_cpu+0x107/0x320 include/linux/filter.h:746\n sk_psock_msg_verdict+0x357/0x7f0 net/core/skmsg.c:934\n tcp_bpf_send_verdict net/ipv4/tcp_bpf.c:420 [inline]\n tcp_bpf_sendmsg+0x766/0x1ae0 net/ipv4/tcp_bpf.c:583\n __sock_sendmsg+0x153/0x1c0 net/socket.c:802\n __sys_sendto+0x326/0x430 net/socket.c:2265\n __x64_sys_sendto+0xe3/0x100 net/socket.c:2268\n do_syscall_64+0x14c/0x480\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \n\nWiden the addition with a (u64) cast so the bound is evaluated in\n64-bit and a len near U32_MAX no longer wraps below msg->sg.size.\n\nWhile here, change pop from int to u32. It counts bytes against the\nunsigned scatterlist lengths and can never be negative, so the signed\ntype only invites sign-confusion in the pop loop." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.4, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The flaw is in the BPF sk_msg helper bpf_msg_pop_data(), reached only from the sockmap egress verdict path via local sendmsg/sendto on a sockmap- or kTLS-attached socket (tcp_bpf_sendmsg/tls_sw_sendmsg → sk_psock_msg_verdict), matching kernel CNA BPF/sockmap Local guidance.\nAC:L - start and len are ARG_ANYTHING (verifier unbounded); an sk_msg program can pick values whose u32 sum wraps below msg->sg.size (e.g. start=100, len≈U32_MAX) and trigger the bad path deterministically with a single sendmsg, with no race or external state.\nPR:N - Triggering corruption requires only sendmsg on a socket already in a sockmap whose SK_MSG program calls bpf_msg_pop_data; on internet-facing kTLS/sockmap L7 proxies an unauthenticated remote client can reach this with no victim credentials, and arg2/arg3 are unconstrained by the verifier.\nUI:N - Exploitation needs only the attacker's own socket traffic and BPF-driven pop parameters; no independent victim mount, file open, or administrator action is required at trigger time.\nS:U - Out-of-bounds scatterlist manipulation corrupts kernel sk_msg/page state within the same kernel security authority and does not by itself cross VM, IOMMU, or hypervisor boundaries.\nC:H - After the overflowed bound check, sk_msg_shift_left() walks past msg->sg.end, reading invalid scatterlist slots and dereferencing bogus page pointers via put_page(), yielding out-of-bounds kernel memory disclosure convertible to arbitrary read.\nI:H - The same over-run writes msg->sg.data[] entries and copy bitmap state beyond the fixed MAX_MSG_FRAGS ring, corrupting adjacent kernel objects with attacker-influenced scatterlist metadata suitable for control-flow hijack and privilege escalation.\nA:H - The fix commit's KASAN trace shows a general protection fault/null-ptr-deref in sk_msg_shift_left() during bpf_msg_pop_data(); this reliably oopses the host and can panic even when full exploitation is not attempted." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/filter.c" ], "versions": [ { "version": "7246d8ed4dcce23f7509949a77be15fa9f0e3d28", "lessThan": "9ef44ed6fb0c1db01cfcc3de432a33e719713eb5", "status": "affected", "versionType": "git" }, { "version": "7246d8ed4dcce23f7509949a77be15fa9f0e3d28", "lessThan": "d693c5ed67dabe1ccbf8dcea93075bdc9ffd4ca0", "status": "affected", "versionType": "git" }, { "version": "7246d8ed4dcce23f7509949a77be15fa9f0e3d28", "lessThan": "ba5cc05dae8fce237d191c7ea96b1107a791e548", "status": "affected", "versionType": "git" }, { "version": "7246d8ed4dcce23f7509949a77be15fa9f0e3d28", "lessThan": "c05a0ec1cdced622a1a0c7d85679fe02f31033ec", "status": "affected", "versionType": "git" }, { "version": "7246d8ed4dcce23f7509949a77be15fa9f0e3d28", "lessThan": "17eb9832a10db2f7a80cb429ca2bc5038445a943", "status": "affected", "versionType": "git" }, { "version": "7246d8ed4dcce23f7509949a77be15fa9f0e3d28", "lessThan": "fe09dd288722f1c749b7506c0b3e7841a7d85027", "status": "affected", "versionType": "git" }, { "version": "7246d8ed4dcce23f7509949a77be15fa9f0e3d28", "lessThan": "e09f7bd7273928b4089e6b71f8e992f2b356ca1b", "status": "affected", "versionType": "git" }, { "version": "7246d8ed4dcce23f7509949a77be15fa9f0e3d28", "lessThan": "a48802fb2cd2d1e23651989f8ff4d15e9d5dad54", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/filter.c" ], "versions": [ { "version": "5.0", "status": "affected" }, { "version": "0", "lessThan": "5.0", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "5.0", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/9ef44ed6fb0c1db01cfcc3de432a33e719713eb5" }, { "url": "https://git.kernel.org/stable/c/d693c5ed67dabe1ccbf8dcea93075bdc9ffd4ca0" }, { "url": "https://git.kernel.org/stable/c/ba5cc05dae8fce237d191c7ea96b1107a791e548" }, { "url": "https://git.kernel.org/stable/c/c05a0ec1cdced622a1a0c7d85679fe02f31033ec" }, { "url": "https://git.kernel.org/stable/c/17eb9832a10db2f7a80cb429ca2bc5038445a943" }, { "url": "https://git.kernel.org/stable/c/fe09dd288722f1c749b7506c0b3e7841a7d85027" }, { "url": "https://git.kernel.org/stable/c/e09f7bd7273928b4089e6b71f8e992f2b356ca1b" }, { "url": "https://git.kernel.org/stable/c/a48802fb2cd2d1e23651989f8ff4d15e9d5dad54" } ], "title": "bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check", "x_generator": { "engine": "bippy-1.2.0" } } } }