{"id":"CVE-2026-98588","title":"bpf, sockmap: Reject max_entries > INT_MAX in sock_map_alloc","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Reject max_entries > INT_MAX in sock_map_alloc\n\nsock_map_alloc() only rejects max_entries == 0 and otherwise allows any\nu32 value.  sock_map_free() then w…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < f4a73f49e256bd835368504462be3b57b03febff","Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < c56191af3a578b9cc265fa3bd5fc0752c59c1781","Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < 909f761868fda329dc69130ef9eb5b5795bcdf00","Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < cc70972ddbf0e3398f2f32624d31db78594d50d8","Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < cea597519b9ca6d691c98d92460ead8ece2a07af","Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < ba7d627dbc67d62df2fa66d7b41e743c3ace0ec8","Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < 814a81c842bd88f6bd8a4ce550d560df071a5d03","Linux 5.11"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:19:00.934Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98588","references":[{"url":"https://git.kernel.org/stable/c/f4a73f49e256bd835368504462be3b57b03febff"},{"url":"https://git.kernel.org/stable/c/c56191af3a578b9cc265fa3bd5fc0752c59c1781"},{"url":"https://git.kernel.org/stable/c/909f761868fda329dc69130ef9eb5b5795bcdf00"},{"url":"https://git.kernel.org/stable/c/cc70972ddbf0e3398f2f32624d31db78594d50d8"},{"url":"https://git.kernel.org/stable/c/cea597519b9ca6d691c98d92460ead8ece2a07af"},{"url":"https://git.kernel.org/stable/c/ba7d627dbc67d62df2fa66d7b41e743c3ace0ec8"},{"url":"https://git.kernel.org/stable/c/814a81c842bd88f6bd8a4ce550d560df071a5d03"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T15:45:12.252Z","slug":"CVE-2026-98588","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Reject max_entries > INT_MAX in sock_map_alloc\n\nsock_map_alloc() only rejects max_entries == 0 and otherwise allows any\nu32 value.  sock_map_free() then walks the sks[] array with a signed int\niterator:\n\n\tint i;\n\tfor (i = 0; i < stab->map.max_entries; i++)\n\t\tstruct sock **psk = &stab->sks[i];\n\nWhen a SOCKMAP is created with max_entries = 0xffffffff (UINT_MAX), the\nallocation of 32 GiB can succeed on large-memory hosts.  During free the\ncounter reaches 0x80000000, wraps to INT_MIN, is sign-extended by movslq\nand turned into a ~16 GiB negative offset from stab->sks, pointing far\nbelow the allocation.\n\nThe faulting access is an xchg() write in sock_map_free().  Without\nKASAN, the same out-of-bounds write can fault on an unmapped vmalloc page\nor corrupt an unrelated allocation if that vmalloc address is populated.\nOn a KASAN kernel with CONFIG_KASAN_VMALLOC=y, the shadow check for that\naddress hits an unmapped shadow page and oopses first:\n\n  BUG: unable to handle page fault for address: fffff521b59c5a00\n  RIP: 0010:kasan_check_range+0x107/0x190\n  Call Trace:\n   sock_map_free+0x93/0x190\n   map_create+0x68d/0xb30\n   __sys_bpf+0x21e/0x2e70\n\nVmcore confirmed stab->map.max_entries == 0xffffffff, stab->sks ==\n0xffffc911ace2d000, and the faulting address sks + (s64)INT_MIN * 8\nexactly at 0xffffc90dace2d000.  The same buggy path is reached on the\nnormal close()/bpf_map_free_deferred() path whenever such a map is\ndestroyed.\n\nsock_map_alloc() used to bound its allocation size through\nbpf_map_charge_init(), but the bound was dropped when rlimit-based memory\naccounting was removed.  Reject max_entries > INT_MAX at creation time so\nthe signed iterator in sock_map_free() never sees a value that would\noverflow.\n\nTriggered by syzkaller and reproduced on both a 6.6-based KASAN kernel\nand the upstream v7.3-rc2 kernel.\n\n## Affected\n\n- `Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < f4a73f49e256bd835368504462be3b57b03febff`\n- `Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < c56191af3a578b9cc265fa3bd5fc0752c59c1781`\n- `Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < 909f761868fda329dc69130ef9eb5b5795bcdf00`\n- `Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < cc70972ddbf0e3398f2f32624d31db78594d50d8`\n- `Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < cea597519b9ca6d691c98d92460ead8ece2a07af`\n- `Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < ba7d627dbc67d62df2fa66d7b41e743c3ace0ec8`\n- `Linux >= 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 < 814a81c842bd88f6bd8a4ce550d560df071a5d03`\n- `Linux 5.11`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}