{"id":"CVE-2026-74256","state":"PUBLISHED","title":"bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check","description":"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   <TASK>\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   </TASK>\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.","publishedAt":"2026-08-15T05:57:34.956Z","updatedAt":"2026-10-16T18:55:28.085Z","severity":{"score":8.4,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"9ef44ed6fb0c1db01cfcc3de432a33e719713eb5","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"d693c5ed67dabe1ccbf8dcea93075bdc9ffd4ca0","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"ba5cc05dae8fce237d191c7ea96b1107a791e548","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"c05a0ec1cdced622a1a0c7d85679fe02f31033ec","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"17eb9832a10db2f7a80cb429ca2bc5038445a943","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"fe09dd288722f1c749b7506c0b3e7841a7d85027","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"e09f7bd7273928b4089e6b71f8e992f2b356ca1b","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"a48802fb2cd2d1e23651989f8ff4d15e9d5dad54","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/filter.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.0","versionType":"semver"},{"version":"5.10.261","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/filter.c"]}],"references":["https://git.kernel.org/stable/c/9ef44ed6fb0c1db01cfcc3de432a33e719713eb5","https://git.kernel.org/stable/c/d693c5ed67dabe1ccbf8dcea93075bdc9ffd4ca0","https://git.kernel.org/stable/c/ba5cc05dae8fce237d191c7ea96b1107a791e548","https://git.kernel.org/stable/c/c05a0ec1cdced622a1a0c7d85679fe02f31033ec","https://git.kernel.org/stable/c/17eb9832a10db2f7a80cb429ca2bc5038445a943","https://git.kernel.org/stable/c/fe09dd288722f1c749b7506c0b3e7841a7d85027","https://git.kernel.org/stable/c/e09f7bd7273928b4089e6b71f8e992f2b356ca1b","https://git.kernel.org/stable/c/a48802fb2cd2d1e23651989f8ff4d15e9d5dad54"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74256.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74256","state":"PUBLISHED","datePublished":"2026-08-15T05:57:34.956Z","dateUpdated":"2026-10-16T18:55:28.085Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.876Z"},"containers":{"cna":{"title":"bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check","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   <TASK>\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   </TASK>\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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"9ef44ed6fb0c1db01cfcc3de432a33e719713eb5","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"d693c5ed67dabe1ccbf8dcea93075bdc9ffd4ca0","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"ba5cc05dae8fce237d191c7ea96b1107a791e548","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"c05a0ec1cdced622a1a0c7d85679fe02f31033ec","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"17eb9832a10db2f7a80cb429ca2bc5038445a943","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"fe09dd288722f1c749b7506c0b3e7841a7d85027","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"e09f7bd7273928b4089e6b71f8e992f2b356ca1b","versionType":"git"},{"version":"7246d8ed4dcce23f7509949a77be15fa9f0e3d28","status":"affected","lessThan":"a48802fb2cd2d1e23651989f8ff4d15e9d5dad54","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/filter.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.0","versionType":"semver"},{"version":"5.10.261","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/filter.c"]}],"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"}],"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."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:45:05.356Z"},"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"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74256","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:51:25.562795Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T18:55:28.085Z"}}]}}}