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Fencer Vulns
medium 5.5

CVE-2026-23114 json

arm64/fpsimd: ptrace: Fix SVE writes on !SME systems

published 2026-02-14 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-6033

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

arm64/fpsimd: ptrace: Fix SVE writes on !SME systems

When SVE is supported but SME is not supported, a ptrace write to the NT_ARM_SVE regset can place the tracee into an invalid state where (non-streaming) SVE register data is stored in FP_STATE_SVE format but TIF_SVE is clear. This can result in a later warning from fpsimd_restore_current_state(), e.g.

WARNING: CPU: 0 PID: 7214 at arch/arm64/kernel/fpsimd.c:383 fpsimd_restore_current_state+0x50c/0x748

When this happens, fpsimd_restore_current_state() will set TIF_SVE, placing the task into the correct state. This occurs before any other check of TIF_SVE can possibly occur, as other checks of TIF_SVE only happen while the FPSIMD/SVE/SME state is live. Thus, aside from the warning, there is no functional issue.

This bug was introduced during rework to error handling in commit:

9f8bf718f2923 ("arm64/fpsimd: ptrace: Gracefully handle errors")

... where the setting of TIF_SVE was moved into a block which is only executed when system_supports_sme() is true.

Fix this by removing the system_supports_sme() check. This ensures that TIF_SVE is set for (SVE-formatted) writes to NT_ARM_SVE, at the cost of unconditionally manipulating the tracee's saved svcr value. The manipulation of svcr is benign and inexpensive, and we already do similar elsewhere (e.g. during signal handling), so I don't think it's worth guarding this with system_supports_sme() checks.

Aside from the above, there is no functional change. The 'type' argument to sve_set_common() is only set to ARM64_VEC_SME (in ssve_set())) when system_supports_sme(), so the ARM64_VEC_SME case in the switch statement is still unreachable when !system_supports_sme(). When CONFIG_ARM64_SME=n, the only caller of sve_set_common() is sve_set(), and the compiler can constant-fold for the case where type is ARM64_VEC_SVE, removing the logic for other cases.

Patch / fix

  • Linux Linux 6.18.8, 6.19
  • linux Debian 14 6.18.8-1

debian advisories DEBIAN-CVE-2026-23114

  • linux-gcp-6.17 Ubuntu 24.04 LTS 6.17.0-1021.24~24.04.1
  • linux-hwe-6.17 Ubuntu 24.04 LTS 6.17.0-41.41~24.04.1
  • linux-oem-6.17 Ubuntu 24.04 LTS 6.17.0-1030.30
  • linux-azure-6.17 Ubuntu 24.04 LTS 6.17.0-1021.21~24.04.1
  • linux-nvidia-6.17 Ubuntu 24.04 LTS 6.17.0-1031.31
  • linux-oracle-6.17 Ubuntu 24.04 LTS 6.17.0-1019.19~24.04.3
  • linux-realtime-6.17 Ubuntu Pro Realtime 24.04 LTS 6.17.0-1018.20~24.04.1

ubuntu advisories UBUNTU-CVE-2026-23114

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-23114 updated cvss 5.5

kernel: arm64/fpsimd: ptrace: Fix SVE writes on !SME systems

  • Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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