Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: gpio: sch: use raw_spinlock_t in the irq startup path sch_irq_unmask() enables… (CVE-2026-64428)
A vulnerability in the Linux kernel's GPIO subsystem was resolved involving improper use of locking primitives in the IRQ startup path. The issue occurs because the sch_irq_unmask() function enables a GPIO IRQ and updates controller state using a spinlock that can become a sleeping lock under PREEMPT_RT, leading to a sleeping function call in an invalid context. This flaw could cause system instability or crashes. The vulnerability has been fixed in updated Linux kernel versions provided by Ubuntu.
AI Analysis
Technical Summary
The Linux kernel vulnerability CVE-2026-64428 concerns the GPIO subsystem's irq startup path where sch_irq_unmask() enables GPIO IRQs and updates controller state via sch_irq_mask_unmask(), which uses spin_lock_irqsave() on sch->lock. On PREEMPT_RT kernels, the regular spinlock_t can become a sleeping lock, but the irq_startup() path is not sleepable, causing a BUG due to a sleeping function called from an invalid context. This was identified by static analysis and confirmed with a proof-of-concept. The issue is resolved by switching to raw_spinlock_t to avoid sleeping in this context. The fix is included in Linux kernel updates distributed by Ubuntu.
Potential Impact
This vulnerability can cause kernel instability or crashes due to improper locking behavior in the GPIO IRQ startup path, especially on PREEMPT_RT (real-time) kernels. It does not directly impact confidentiality or integrity but affects availability by potentially causing system faults. The CVSS score is 5.5 (medium severity) with an impact on availability only. There are no known exploits in the wild.
Mitigation Recommendations
A patch is available and included in updated Linux kernel packages from Ubuntu. Users should apply the official kernel updates for their respective Ubuntu releases and reboot systems to apply the fix. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be required. Follow the Ubuntu security notices USN-8726-1 and USN-8727-1 for detailed update instructions.
Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: gpio: sch: use raw_spinlock_t in the irq startup path sch_irq_unmask() enables… (CVE-2026-64428)
Description
A vulnerability in the Linux kernel's GPIO subsystem was resolved involving improper use of locking primitives in the IRQ startup path. The issue occurs because the sch_irq_unmask() function enables a GPIO IRQ and updates controller state using a spinlock that can become a sleeping lock under PREEMPT_RT, leading to a sleeping function call in an invalid context. This flaw could cause system instability or crashes. The vulnerability has been fixed in updated Linux kernel versions provided by Ubuntu.
CVSS v3.1
Score 5.5medium
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel vulnerability CVE-2026-64428 concerns the GPIO subsystem's irq startup path where sch_irq_unmask() enables GPIO IRQs and updates controller state via sch_irq_mask_unmask(), which uses spin_lock_irqsave() on sch->lock. On PREEMPT_RT kernels, the regular spinlock_t can become a sleeping lock, but the irq_startup() path is not sleepable, causing a BUG due to a sleeping function called from an invalid context. This was identified by static analysis and confirmed with a proof-of-concept. The issue is resolved by switching to raw_spinlock_t to avoid sleeping in this context. The fix is included in Linux kernel updates distributed by Ubuntu.
Potential Impact
This vulnerability can cause kernel instability or crashes due to improper locking behavior in the GPIO IRQ startup path, especially on PREEMPT_RT (real-time) kernels. It does not directly impact confidentiality or integrity but affects availability by potentially causing system faults. The CVSS score is 5.5 (medium severity) with an impact on availability only. There are no known exploits in the wild.
Mitigation Recommendations
A patch is available and included in updated Linux kernel packages from Ubuntu. Users should apply the official kernel updates for their respective Ubuntu releases and reboot systems to apply the fix. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be required. Follow the Ubuntu security notices USN-8726-1 and USN-8727-1 for detailed update instructions.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-3jvv-rp8p-q944
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-64428"]
- Ecosystems
- []
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a6542099c2644c7f80838e1
Added to database: 07/25/2026, 23:08:57 UTC
Last enriched: 09/07/2026, 17:58:21 UTC
Last updated: 09/07/2026, 17:58:21 UTC
Views: 42
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