arm64/fpsimd: signal: Forbid non-streaming SVE payload on SME-only systems
Severity and exploitation
KEV coverage does not rule out exploitation.
Severity
unknownCVSS measures technical severity, not the likelihood of an attack.
Known exploitation
Not listed in the checked CISA KEV catalog
Absence from CISA KEV does not rule out attacks.
Public exploit
Not established by this record
Missing evidence does not mean no public exploit exists.
Remediation
Fix status not established
No structured fix or guidance is available here. Check the latest publisher advisory.
What this means
In the Linux kernel, the following vulnerability has been resolved:
Source excerpt · LinuxAttack conditions
No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.
Review supporting sources →Affected versions
Check the exact model, release, and any platform requirements against your installation.
Linux · Linux
Linux
7 ranges
Linux · Linux
Linux
Compare with this publisher’s ranges. This does not inspect your installation.
affected
05458ee3ff82b31a4564836a84ef20d6c233dfc7 → before 6c5b3ec340921617d965b7c87959560e886e778f
git versions
7dde62f0687c8856b6c0660066c7ee83a6a6f033 → before 052acee9880114879b5c221fc8dad69b786d0938
git versions
7dde62f0687c8856b6c0660066c7ee83a6a6f033 → before f2338929c7663859c0c74dd6fef2c0245066f845
git versions
7dde62f0687c8856b6c0660066c7ee83a6a6f033 → before 2bce6f006cfe0b60e8249fd8d51396d99355cba3
git versions
7dde62f0687c8856b6c0660066c7ee83a6a6f033 → before 88c1c611552b24658eb61244086691c02be2013b
git versions
7dde62f0687c8856b6c0660066c7ee83a6a6f033 → before e060d9069b49fe55f38057dfe592068014652671
git versions
6.1.7 → before 6.1.191
semver versions
Other versions: unaffected
Linux · Linux
Linux
8 ranges
Linux · Linux
Linux
Compare with this publisher’s ranges. This does not inspect your installation.
affected
6.2
unaffected
0 → before 6.2
semver versions
6.1.191 → through 6.1.*
semver versions
6.6.160 → through 6.6.*
semver versions
6.12.113 → through 6.12.*
semver versions
6.18.56 → through 6.18.*
semver versions
7.2.10 → through 7.2.*
semver versions
7.3 → through *
original_commit_for_fix versions
Other versions: affected
What to do
Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.
No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.
cve.new guidance unless attributed to a publisher. This page does not inspect your installation.
Public exploit evidence
No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.
Original source description
Read the full publisher 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's 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's 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's 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 +PAN -UAO -TCO +DIT -SSBS BTYPE=--) | pc : fpsimd_restore_current_state+0x258/0x458 | lr : exit_to_user_mode_loop+0xb8/0x188 | 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+0x258/0x458 (P) | exit_to_user_mode_loop+0xb8/0x188 | el0_svc+0x1cc/0x1d0 | el0t_64_sync_handler+0xa0/0xe4 | el0t_64_sync+0x198/0x19c | 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't necessary for restore_sve_fpsimd_context() to handle the case where neither are supported.
References
6 sourcesInside the record
Evidence available
Describes the evidence in this view, not whether the product is safe.
Original records
CVE-2026-98745View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.
cve.new JSON →Environment requirements
These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.
Linux · platform conditions
Any condition may hold
Vulnerable product
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*From (inclusive): 6.1.7
Before: 6.1.191
Vulnerable product
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*From (inclusive): 6.2
Before: 6.6.160
Vulnerable product
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*From (inclusive): 6.2
Before: 6.12.113
Vulnerable product
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*From (inclusive): 6.2
Before: 6.18.56
Vulnerable product
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*From (inclusive): 6.2
Before: 7.2.10
Vulnerable product
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*From (inclusive): 6.2
Before: 7.3
Applicability preview
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]Contributing organizations · 1
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Last imported by cve.new
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What changed
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