Vulnerability in Linux kernel (CVE-2026-98745)
Summary
Vulnerability in Linux kernel (CVE-2026-98745). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-98745 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-98745" on the vendor's site.
CVE-2026-98745 (Linux kernel)
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-98745 linux
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com