{"id":"CVE-2026-74256","title":"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 be…","summary":"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 be…","severity":"high","cvss":8.4,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-476"],"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 6","enterprise_linux 8","enterprise_linux 9"],"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T19:17:34.317","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74256","references":[{"url":"https://git.kernel.org/stable/c/17eb9832a10db2f7a80cb429ca2bc5038445a943","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9ef44ed6fb0c1db01cfcc3de432a33e719713eb5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a48802fb2cd2d1e23651989f8ff4d15e9d5dad54","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ba5cc05dae8fce237d191c7ea96b1107a791e548","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c05a0ec1cdced622a1a0c7d85679fe02f31033ec","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d693c5ed67dabe1ccbf8dcea93075bdc9ffd4ca0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e09f7bd7273928b4089e6b71f8e992f2b356ca1b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fe09dd288722f1c749b7506c0b3e7841a7d85027","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74256.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-74256"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2516834"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74256"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74256"},{"url":"https://kernelcve.org/list/?q=CVE-2026-74256"},{"url":"https://lore.kernel.org/linux-cve-announce/2026081541-CVE-2026-74256-a6a4@gregkh/T"}],"tags":["nvd","csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00185,"epssPercentile":0.08013,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T18:51:25.562795Z"},"scores":{"nvd":8.4,"vendor":5.5,"cna":8.4},"ingestedAt":"2026-10-16T19:46:24.388Z","slug":"CVE-2026-74256","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74256.json)","depth":"twilight","depthScore":46,"depthScoreParts":{"impact":46.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":230313,"id":"CVE-2026-74256","ts":1793130917364,"field":"cvss","old":"5.5","new":"8.4"},{"seq":230312,"id":"CVE-2026-74256","ts":1793130917364,"field":"severity","old":"medium","new":"high"},{"seq":229392,"id":"CVE-2026-74256","ts":1793019728416,"field":"cvss","old":"8.4","new":"5.5"},{"seq":229391,"id":"CVE-2026-74256","ts":1793019728416,"field":"severity","old":"high","new":"medium"}]}