Linux Kernel up to 6.1.158/6.6.116/6.12.57/6.17.7 fpu__clear_user_states denial of service

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CTI Interest Score
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4.6$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.158/6.6.116/6.12.57/6.17.7 and classified as critical. The affected element is the function fpu__clear_user_states. Executing a manipulation can lead to denial of service. This vulnerability is registered as CVE-2025-68171. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.158/6.6.116/6.12.57/6.17.7. It has been declared as critical. This vulnerability affects the function fpu__clear_user_states. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Ensure XFD state on signal delivery Sean reported [1] the following splat when running KVM tests: WARNING: CPU: 232 PID: 15391 at xfd_validate_state+0x65/0x70 Call Trace: <TASK> fpu__clear_user_states+0x9c/0x100 arch_do_signal_or_restart+0x142/0x210 exit_to_user_mode_loop+0x55/0x100 do_syscall_64+0x205/0x2c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Chao further identified [2] a reproducible scenario involving signal delivery: a non-AMX task is preempted by an AMX-enabled task which modifies the XFD MSR. When the non-AMX task resumes and reloads XSTATE with init values, a warning is triggered due to a mismatch between fpstate::xfd and the CPU's current XFD state. fpu__clear_user_states() does not currently re-synchronize the XFD state after such preemption. Invoke xfd_update_state() which detects and corrects the mismatch if there is a dynamic feature. This also benefits the sigreturn path, as fpu__restore_sig() may call fpu__clear_user_states() when the sigframe is inaccessible. [ dhansen: minor changelog munging ]

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2025-68171 since 12/16/2025. The exploitation appears to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 282382 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1350)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.159, 6.6.117, 6.12.58 or 6.17.8 eliminates this vulnerability. Applying the patch eefbfb722042fc9210d2e0ac2b063fd1abf51895/1811c610653c0cd21cc9add14595b7cffaeca511/5b2619b488f1d08b960c43c6468dd0759e8b3035/3f735419c4b43cde42e6d408db39137b82474e31/388eff894d6bc5f921e9bfff0e4b0ab2684a96e9 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 (282382) and CERT Bund (WID-SEC-2025-2868). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.6

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 282382
Nessus Name: Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1350)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.159/6.6.117/6.12.58/6.17.8
Patch: eefbfb722042fc9210d2e0ac2b063fd1abf51895/1811c610653c0cd21cc9add14595b7cffaeca511/5b2619b488f1d08b960c43c6468dd0759e8b3035/3f735419c4b43cde42e6d408db39137b82474e31/388eff894d6bc5f921e9bfff0e4b0ab2684a96e9

Timelineinfo

12/16/2025 Advisory disclosed
12/16/2025 +0 days CVE reserved
12/16/2025 +0 days VulDB entry created
02/21/2026 +67 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-68171 (🔒)
GCVE (CVE): GCVE-0-2025-68171
GCVE (VulDB): GCVE-100-336760
CERT Bund: WID-SEC-2025-2868 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 12/16/2025 16:00
Updated: 02/21/2026 04:30
Changes: 12/16/2025 16:00 (58), 12/17/2025 08:03 (1), 01/08/2026 23:34 (2), 01/14/2026 03:09 (7), 01/19/2026 21:29 (1), 02/02/2026 13:18 (1), 02/21/2026 04:30 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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