{"id":"CVE-2026-98745","aliases":[],"cve":{"records":[{"id":"CVE-2026-98745","source":"Linux","state":"PUBLISHED","reasons":[],"replacements":[],"disputed":false,"unsupportedWhenAssigned":false,"reserved":"2026-09-25T10:25:14.367Z","published":"2026-10-18T15:47:30.967Z","modified":"2026-10-30T12:39:17.288Z"}],"publishers":[{"name":"Linux","role":"CNA","organizationId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","modified":"2026-10-30T12:39:17.288Z"}],"references":[{"url":"https://git.kernel.org/stable/c/6c5b3ec340921617d965b7c87959560e886e778f","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/052acee9880114879b5c221fc8dad69b786d0938","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/f2338929c7663859c0c74dd6fef2c0245066f845","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/2bce6f006cfe0b60e8249fd8d51396d99355cba3","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/88c1c611552b24658eb61244086691c02be2013b","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/e060d9069b49fe55f38057dfe592068014652671","tags":[],"source":"Linux"}],"weaknesses":[],"applicability":[{"source":"Linux","statements":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.7","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.3"}]}]}]}],"prioritization":[]},"title":"arm64/fpsimd: signal: Forbid non-streaming SVE payload on SME-only systems","titleSource":"Linux","descriptionSource":"Linux","description":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64/fpsimd: signal: Forbid non-streaming SVE payload on SME-only systems\n\nWhen system_supports_sme() is true but system_supports_sve() is false,\nrestoring a specifically crafted SVE signal context can result in the\ntask erroneously having non-streaming SVE state. Subsequent attempts to\nmanipulate the task's FPSIMD/SVE/SME state can result in a variety of\nproblems, including fatal EL1 UNDEFs.\n\nIn such configurations, the kernel always creates an SVE signal context\nwhen delivering a signal, and this can only be in one of two states:\n\n(1) SVE_SIG_FLAG_SM is set, and an SVE payload is present containing\n    streaming mode SVE state. The recorded VL is the task's live\n    streaming VL.\n\n(2) SVE_SIG_FLAG_SM is clear, and an SVE payload is not present. The\n    FPSIMD context contains the non-streaming mode FPSIMD state. The\n    recorded VL is 0.\n\nCurrently restore_sve_fpsimd_context() correctly rejects cases where\nSVE_SIG_FLAG_SM is set and an SVE payload is not present, but fails to\nreject cases where SVE_SIG_FLAG_SM is clear and an SVE payload is\npresent. Consequently, restore_sve_fpsimd_context() can place the task\nin a state where it has non-streaming SVE state even when this is not\nsupported by HW.\n\nFor example, this can cause a later EL1 UNDEF when the kernel attempts to\nrestore the task's ZCR_EL1 value:\n\n| # ./sme-sigcontext-to-sve\n| Internal error: Oops - Undefined instruction: 0000000002000000 [#1]  SMP\n| Modules linked in:\n| CPU: 0 UID: 0 PID: 131 Comm: sme-sigcontext- Not tainted 7.3.0-rc1 #1 PREEMPT\n| Hardware name: linux,dummy-virt (DT)\n| pstate: 61402009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)\n| pc : fpsimd_restore_current_state+0x258/0x458\n| lr : exit_to_user_mode_loop+0xb8/0x188\n| sp : ffff80008056be40\n| x29: ffff80008056be40 x28: fff00000c1670000 x27: 0000000000000000\n| x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000\n| x23: ffff80008056bec0 x22: 0000000000000008 x21: 0000000000000040\n| x20: 0000000000000081 x19: 0000000008800010 x18: 0000000000000000\n| x17: 0000fffffd412570 x16: 0000000000001000 x15: 0000fffffd4123b0\n| x14: 0000fffffd412780 x13: 0000fffffd412be8 x12: 0000000047435300\n| x11: 0000fffffd412570 x10: 0000000000000000 x9 : 0000000045585401\n| x8 : fff00000c18a6c44 x7 : 0000000000000000 x6 : 0000000000000002\n| x5 : 0000000000000002 x4 : ffff800080568000 x3 : 0000000000000001\n| x2 : 0000000008800010 x1 : fff00000c1670000 x0 : 0000000008800000\n| Call trace:\n|  fpsimd_restore_current_state+0x258/0x458 (P)\n|  exit_to_user_mode_loop+0xb8/0x188\n|  el0_svc+0x1cc/0x1d0\n|  el0t_64_sync_handler+0xa0/0xe4\n|  el0t_64_sync+0x198/0x19c\n| Code: d5384101 f9400020 53175c03 36b80de0 (d5381202)\n| ---[ end trace 0000000000000000 ]---\n| Kernel panic - not syncing: Oops - Undefined instruction: Fatal exception in interrupt\n| Kernel Offset: 0x291fb1000000 from 0xffff800080000000\n| PHYS_OFFSET: 0x40000000\n| CPU features: 0x0,00000000,0052802f,ffb88f43,3afcf73f\n| Memory Limit: none\n\nRework restore_sve_fpsimd_context() to reject cases where\nSVE_SIG_FLAG_SM is clear and an SVE payload is not present. As\nparse_user_sigframe() rejects SVE signal frames when neither SVE nor SME\nare supported, it isn't necessary for restore_sve_fpsimd_context() to\nhandle the case where neither are supported.","score":null,"severity":"unknown","published":"2026-10-18T15:47:30.967Z","modified":"2026-10-30T12:39:17.288Z","withdrawn":false,"knownExploited":false,"affected":[],"products":[{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"05458ee3ff82b31a4564836a84ef20d6c233dfc7","status":"affected","lessThan":"6c5b3ec340921617d965b7c87959560e886e778f","versionType":"git"},{"version":"7dde62f0687c8856b6c0660066c7ee83a6a6f033","status":"affected","lessThan":"052acee9880114879b5c221fc8dad69b786d0938","versionType":"git"},{"version":"7dde62f0687c8856b6c0660066c7ee83a6a6f033","status":"affected","lessThan":"f2338929c7663859c0c74dd6fef2c0245066f845","versionType":"git"},{"version":"7dde62f0687c8856b6c0660066c7ee83a6a6f033","status":"affected","lessThan":"2bce6f006cfe0b60e8249fd8d51396d99355cba3","versionType":"git"},{"version":"7dde62f0687c8856b6c0660066c7ee83a6a6f033","status":"affected","lessThan":"88c1c611552b24658eb61244086691c02be2013b","versionType":"git"},{"version":"7dde62f0687c8856b6c0660066c7ee83a6a6f033","status":"affected","lessThan":"e060d9069b49fe55f38057dfe592068014652671","versionType":"git"},{"version":"6.1.7","status":"affected","lessThan":"6.1.191","versionType":"semver"}],"defaultStatus":"unaffected","cpes":[],"source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-98745"},{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"defaultStatus":"affected","cpes":[],"source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-98745"}],"remediation":[],"references":["https://git.kernel.org/stable/c/6c5b3ec340921617d965b7c87959560e886e778f","https://git.kernel.org/stable/c/052acee9880114879b5c221fc8dad69b786d0938","https://git.kernel.org/stable/c/f2338929c7663859c0c74dd6fef2c0245066f845","https://git.kernel.org/stable/c/2bce6f006cfe0b60e8249fd8d51396d99355cba3","https://git.kernel.org/stable/c/88c1c611552b24658eb61244086691c02be2013b","https://git.kernel.org/stable/c/e060d9069b49fe55f38057dfe592068014652671"],"sources":[{"name":"CVE","id":"CVE-2026-98745","modified":"2026-10-30T12:39:17.288Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-98745"}],"assessments":[],"sourceAffected":[],"observedAt":"2026-10-30T14:04:45.865Z","kev":{"status":"not-listed","checkedAt":"2026-11-15T00:05:31.288Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[],"aiSummary":null}