Linux Kernel up to 6.1.141/6.6.93/6.12.33/6.15.2 do_sme_acc data authenticity

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4.9$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.141/6.6.93/6.12.33/6.15.2. It has been rated as problematic. The affected element is the function do_sme_acc. Performing a manipulation results in data authenticity. This vulnerability is reported as CVE-2025-38170. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.141/6.6.93/6.12.33/6.15.2. It has been classified as problematic. This affects the function do_sme_acc. The manipulation with an unknown input leads to a data authenticity vulnerability. CWE is classifying the issue as CWE-345. The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: arm64/fpsimd: Discard stale CPU state when handling SME traps The logic for handling SME traps manipulates saved FPSIMD/SVE/SME state incorrectly, and a race with preemption can result in a task having TIF_SME set and TIF_FOREIGN_FPSTATE clear even though the live CPU state is stale (e.g. with SME traps enabled). This can result in warnings from do_sme_acc() where SME traps are not expected while TIF_SME is set: | /* With TIF_SME userspace shouldn't generate any traps */ | if (test_and_set_thread_flag(TIF_SME)) | WARN_ON(1); This is very similar to the SVE issue we fixed in commit: 751ecf6afd6568ad ("arm64/sve: Discard stale CPU state when handling SVE traps") The race can occur when the SME trap handler is preempted before and after manipulating the saved FPSIMD/SVE/SME state, starting and ending on the same CPU, e.g. | void do_sme_acc(unsigned long esr, struct pt_regs *regs) | { | // Trap on CPU 0 with TIF_SME clear, SME traps enabled | // task->fpsimd_cpu is 0. | // per_cpu_ptr(&fpsimd_last_state, 0) is task. | | ... | | // Preempted; migrated from CPU 0 to CPU 1. | // TIF_FOREIGN_FPSTATE is set. | | get_cpu_fpsimd_context(); | | /* With TIF_SME userspace shouldn't generate any traps */ | if (test_and_set_thread_flag(TIF_SME)) | WARN_ON(1); | | if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { | unsigned long vq_minus_one = | sve_vq_from_vl(task_get_sme_vl(current)) - 1; | sme_set_vq(vq_minus_one); | | fpsimd_bind_task_to_cpu(); | } | | put_cpu_fpsimd_context(); | | // Preempted; migrated from CPU 1 to CPU 0. | // task->fpsimd_cpu is still 0 | // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then: | // - Stale HW state is reused (with SME traps enabled) | // - TIF_FOREIGN_FPSTATE is cleared | // - A return to userspace skips HW state restore | } Fix the case where the state is not live and TIF_FOREIGN_FPSTATE is set by calling fpsimd_flush_task_state() to detach from the saved CPU state. This ensures that a subsequent context switch will not reuse the stale CPU state, and will instead set TIF_FOREIGN_FPSTATE, forcing the new state to be reloaded from memory prior to a return to userspace. Note: this was originallly posted as [1]. [ Rutland: rewrite commit message ]

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2025-38170 since 04/16/2025. The exploitability is told to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 249177 (Debian dsa-5973 : affs-modules-6.1.0-37-4kc-malta-di - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.142, 6.6.94, 6.12.34, 6.15.3 or 6.16-rc1 eliminates this vulnerability. Applying the patch de89368de3894a8db27caeb8fd902ba1c49f696a/43be952e885476dafb74aa832c0847b2f4f650c6/6103f9ba51a59afb5a0f32299c837377c5a5a693/c4a4786d93e99517d6f10ed56b9ffba4ce88d3b3/d3eaab3c70905c5467e5c4ea403053d67505adeb is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (249177), EUVD (EUVD-2025-19774) and CERT Bund (WID-SEC-2025-1452). Be aware that VulDB is the high quality source for vulnerability data.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Dell Avamar
  • Open Source Linux Kernel
  • Dell NetWorker
  • Dell Secure Connect Gateway

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.0
VulDB Meta Temp Score: 4.9

VulDB Base Score: 4.6
VulDB Temp Score: 4.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Data authenticity
CWE: CWE-345
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 249177
Nessus Name: Debian dsa-5973 : affs-modules-6.1.0-37-4kc-malta-di - security update

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.142/6.6.94/6.12.34/6.15.3/6.16-rc1
Patch: de89368de3894a8db27caeb8fd902ba1c49f696a/43be952e885476dafb74aa832c0847b2f4f650c6/6103f9ba51a59afb5a0f32299c837377c5a5a693/c4a4786d93e99517d6f10ed56b9ffba4ce88d3b3/d3eaab3c70905c5467e5c4ea403053d67505adeb

Timelineinfo

04/16/2025 CVE reserved
07/03/2025 +78 days Advisory disclosed
07/03/2025 +0 days VulDB entry created
12/19/2025 +169 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-38170 (🔒)
GCVE (CVE): GCVE-0-2025-38170
GCVE (VulDB): GCVE-100-314727
EUVD: 🔒
CERT Bund: WID-SEC-2025-1452 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 07/03/2025 12:12
Updated: 12/19/2025 03:25
Changes: 07/03/2025 12:12 (57), 07/03/2025 12:29 (1), 08/13/2025 19:43 (2), 08/23/2025 22:14 (7), 09/22/2025 00:27 (1), 11/09/2025 17:08 (1), 12/06/2025 20:09 (1), 12/19/2025 03:25 (12)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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