CVE-2025-68757

System hang via IRQ-unsafe fence timer deletion

Published Jan 5, 2026 · Updated Jan 5, 2026

Deadlock in the Linux kernel VGEM fence code allows local users to hang the system by releasing a fence while its timer runs. vgem_fence_release calls timer_delete_sync on the fence timer without marking that timer TIMER_IRQSAFE, so IRQ-context release can reacquire the timer lock already held by the interrupt path. Reachability requires the VGEM driver and a fence-release race in IRQ context; the demonstrated consequence is a kernel deadlock and service hang, not data access or code execution.

CVSS severity6.2
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deadlock in the Linux kernel VGEM fence code allows local users to hang the system by releasing a fence while its timer runs. vgem_fence_release calls timer_delete_sync on the fence timer without marking that timer TIMER_IRQSAFE, so IRQ-context release can reacquire the timer lock already held by the interrupt path. Reachability requires the VGEM driver and a fence-release race in IRQ context; the demonstrated consequence is a kernel deadlock and service hang, not data access or code execution.

The record

CVE
CVE-2025-68757
Published
Jan 5, 2026
Updated
Jan 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4077798484459a2eced2050045099a466ecb618a <1f0ca9d3e7c38a39f1f12377c24decf0bba46e54
  2. Affected versionversion=4077798484459a2eced2050045099a466ecb618a <338e388c0d80ffc04963b6b0ec702ffdfd2c4eba
  3. Affected versionversion=4077798484459a2eced2050045099a466ecb618a <4f335cb8fad69b2be5accf0ebac3a8b345915f4e
  4. Affected versionversion=4077798484459a2eced2050045099a466ecb618a <78b4d6463e9e69e5103f98b367f8984ad12cdc6f
  5. Affected versionversion=4.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4077798484459a2eced2050045099a466ecb618a <1f0ca9d3e7c38a39f1f12377c24decf0bba46e54; version=4077798484459a2eced2050045099a466ecb618a <338e388c0d80ffc04963b6b0ec702ffdfd2c4eba; version=4077798484459a2eced2050045099a466ecb618a <4f335cb8fad69b2be5accf0ebac3a8b345915f4e; version=4077798484459a2eced2050045099a466ecb618a <78b4d6463e9e69e5103f98b367f8984ad12cdc6f; version=4.8

Published CVSS scores

6.2Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.2Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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