ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 6 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set, a user fault may trigger show_pte() without any lock. If another thread in the same process concurrently calls munmap(), the page table pages may be freed while show_pte() is still traversing them, causing a use-after-free in show_pte(). If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table of PMD are freed when show_pte() is running. Acquire mmap_write_lock() around show_pte() for user faults to fix the contention. For user faults, additionally restrict that show_pte() is called only when the addr is a user-space address (addr < TASK_SIZE). This is because the lock of tsk->mm only protects the virtual memory of user address space, furthermore, dumping the page tables of a kernel-space address for user faults is unnecessary and may have security implications. Keep everything unchanged for kernel faults, because the kernel is already in the "oops" state, acquiring a lock may risk a deadlock.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-90303
- 2026-10-03 Alias added: GHSA-3rvr-4rpw-5w37
- 2026-10-15 Affected versions changed · Red Hat
- 2026-10-15 CVSS score added · Red Hat
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-23 Affected versions changed · Red Hat
- 2026-10-23 CVSS score changed · Red Hat
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/ab14f07952adfe735d86a53518f8cd576dfd5892
- https://git.kernel.org/stable/c/07e4d5380f2a844ab7a1b440dde350caf561cbb0
- https://git.kernel.org/stable/c/2a14d7797a49a47bccd1a9327fd69da838dcb0dd
- https://git.kernel.org/stable/c/63e3c958a602d0896a101a897c2361878c266ca7
- https://git.kernel.org/stable/c/59bbf86d0ff9373bfa033ca123c1e924f09f1eba
- https://git.kernel.org/stable/c/c71f9a56520b419e55d173052629f2324deb5549
- https://git.kernel.org/stable/c/720408d98d9fb3c91a12090436734c8c61f04545
- https://git.kernel.org/stable/c/1039bffd6ae9c75b42b7d148d6c1106134107b66
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Sources
- CVE-2026-90303 · CVE Program
- CVE-2026-90303 · NVD
- FIRST EPSS
- GHSA-3rvr-4rpw-5w37 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-90303 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences