{ "cveId": "CVE-2026-98745", "url": "https://patchblox.com/security/cve/CVE-2026-98745", "summary": "CVE-2026-98745 is fixed in 21 products on 1 platform, first by DEBIAN-CVE-2026-98745, released October 19, 2026. It is not reported as exploited. Patch Radar priority: Routine.", "title": "arm64/fpsimd: signal: Forbid non-streaming SVE payload on SME-only systems", "description": "In the Linux kernel, the following vulnerability has been resolved: arm64/fpsimd: signal: Forbid non-streaming SVE payload on SME-only systems When system_supports_sme() is true but system_supports_sve() is false, restoring a specifically crafted SVE signal context can result in the task erroneously having non-streaming SVE state. Subsequent attempts to manipulate the task\u0027s FPSIMD/SVE/SME state can result in a variety of problems, including fatal EL1 UNDEFs. In such configurations, the kernel always creates an SVE signal context when delivering a signal, and this can only be in one of two states: (1) SVE_SIG_FLAG_SM is set, and an SVE payload is present containing streaming mode SVE state. The recorded VL is the task\u0027s live streaming VL. (2) SVE_SIG_FLAG_SM is clear, and an SVE payload is not present. The FPSIMD context contains the non-streaming mode FPSIMD state. The recorded VL is 0. Currently restore_sve_fpsimd_context() correctly rejects cases where SVE_SIG_FLAG_SM is set and an SVE payload is not present, but fails to reject cases where SVE_SIG_FLAG_SM is clear and an SVE payload is present. Consequently, restore_sve_fpsimd_context() can place the task in a state where it has non-streaming SVE state even when this is not supported by HW. For example, this can cause a later EL1 UNDEF when the kernel attempts to restore the task\u0027s ZCR_EL1 value: | # ./sme-sigcontext-to-sve | Internal error: Oops - Undefined instruction: 0000000002000000 [#1] SMP | Modules linked in: | CPU: 0 UID: 0 PID: 131 Comm: sme-sigcontext- Not tainted 7.3.0-rc1 #1 PREEMPT | Hardware name: linux,dummy-virt (DT) | pstate: 61402009 (nZCv daif \u002BPAN -UAO -TCO \u002BDIT -SSBS BTYPE=--) | pc : fpsimd_restore_current_state\u002B0x258/0x458 | lr : exit_to_user_mode_loop\u002B0xb8/0x188 | sp : ffff80008056be40 | x29: ffff80008056be40 x28: fff00000c1670000 x27: 0000000000000000 | x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 | x23: ffff80008056bec0 x22: 0000000000000008 x21: 0000000000000040 | x20: 0000000000000081 x19: 0000000008800010 x18: 0000000000000000 | x17: 0000fffffd412570 x16: 0000000000001000 x15: 0000fffffd4123b0 | x14: 0000fffffd412780 x13: 0000fffffd412be8 x12: 0000000047435300 | x11: 0000fffffd412570 x10: 0000000000000000 x9 : 0000000045585401 | x8 : fff00000c18a6c44 x7 : 0000000000000000 x6 : 0000000000000002 | x5 : 0000000000000002 x4 : ffff800080568000 x3 : 0000000000000001 | x2 : 0000000008800010 x1 : fff00000c1670000 x0 : 0000000008800000 | Call trace: | fpsimd_restore_current_state\u002B0x258/0x458 (P) | exit_to_user_mode_loop\u002B0xb8/0x188 | el0_svc\u002B0x1cc/0x1d0 | el0t_64_sync_handler\u002B0xa0/0xe4 | el0t_64_sync\u002B0x198/0x19c | Code: d5384101 f9400020 53175c03 36b80de0 (d5381202) | ---[ end trace 0000000000000000 ]--- | Kernel panic - not syncing: Oops - Undefined instruction: Fatal exception in interrupt | Kernel Offset: 0x291fb1000000 from 0xffff800080000000 | PHYS_OFFSET: 0x40000000 | CPU features: 0x0,00000000,0052802f,ffb88f43,3afcf73f | Memory Limit: none Rework restore_sve_fpsimd_context() to reject cases where SVE_SIG_FLAG_SM is clear and an SVE payload is not present. As parse_user_sigframe() rejects SVE signal frames when neither SVE nor SME are supported, it isn\u0027t necessary for restore_sve_fpsimd_context() to handle the case where neither are supported.", "published": "2026-10-18T16:17:28Z", "severity": "Moderate", "cvss": 4.7, "epss": 0.00172, "epssPercentile": 0.0667, "priority": "Routine", "priorityTier": 4, "exploited": false, "vendorExploited": false, "disclosed": false, "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98745", "fixes": [ { "platform": "linux", "product": "bpftool6.18", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "bpftool6.18-debuginfo", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel-livepatch-6.18.56-125.164", "release": "amzn 2023", "fixedVersion": "1:1.0-0.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-debuginfo", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-debuginfo-common-aarch64", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-debuginfo-common-x86_64", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-devel", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-headers", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-modules-extra", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-modules-extra-common", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-tools", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-tools-debuginfo", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "kernel6.18-tools-devel", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "linux", "release": "Debian 13.5 (trixie)", "fixedVersion": "6.12.113-1", "fix": "DEBIAN-CVE-2026-98745", "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98745", "released": "2026-10-19T16:27:52Z" }, { "platform": "linux", "product": "linux", "release": "Debian 14", "fixedVersion": "7.2.10-1", "fix": "DEBIAN-CVE-2026-98745", "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98745", "released": "2026-10-19T16:27:52Z" }, { "platform": "linux", "product": "linux-6.12", "release": "Debian 12.15 (bookworm)", "fixedVersion": "6.12.113-1~deb12u1", "fix": "DEBIAN-CVE-2026-98745", "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98745", "released": "2026-10-19T16:27:52Z" }, { "platform": "linux", "product": "microvm-kernel6.18", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "perf6.18", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "perf6.18-debuginfo", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "python3-perf6.18", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" }, { "platform": "linux", "product": "python3-perf6.18-debuginfo", "release": "amzn 2023", "fixedVersion": "1:6.18.56-125.164.amzn2023", "fix": "ALAS2023-2026-3251", "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3251", "released": "2026-11-07T01:06:52Z" } ], "noFixYet": [], "dataAsOf": "2026-11-08T06:59:42Z", "attribution": { "text": "Data: Patchblox Patch Radar", "url": "https://patchblox.com/security/patch-radar", "terms": "https://patchblox.com/security/patch-radar/use-the-data" } }