CVE-2026-98505: Linux Vulnerability

Description

In the Linux kernel, the following vulnerability has been resolved: mm/damon/vaddr: avoid hw-driven pte updates during damon_hugetlb_mkold() damon_hugetlb_mkold() reads the page table entry into a local variable, unsets the accessed bit in the variable, and updates the page table entry with the updated variable value. If hardware updates the same page table entry in parallel, the hw updates could be lost. For example, hardware-updated dirty bits might be lost. Avoid the parallel updates by clearing the page table entry when reading it together, using huge_ptep_get_and_clear(). If a parallel write to the memory is made after the clearing, the hw will see the page table entry is cleared, trigger page fault and wait until it is handled. The page fault handling will wait for damon_hugetlb_mkold() due to the page table lock. Because hugetlbfs is an in-memory file system and hugetlb pages cannot be reclaimed, no critical issue is expected to my best knowledge. But definitely this is a nasty bug that should be fixed sooner rather than later. The issue was discovered [1] by Sashiko.

Metrics

EPSS Probability

0.20%

9.2th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 49f4203aae06ba9d67b500c90339b262b0a52637, < 7ed1062d154ec2401f2c894fd6858598bb1160b6; >= 49f4203aae06ba9d67b500c90339b262b0a52637, < 00457981327c80bcc56e07d4714fe189337a19fa; >= 49f4203aae06ba9d67b500c90339b262b0a52637, < e59cb7eda7c06334a0faf5aa44adb6acf2a1287a; >= 49f4203aae06ba9d67b500c90339b262b0a52637, < 6e74ffc9ecf6ec24eee117150da78a1102be74c5; >= 49f4203aae06ba9d67b500c90339b262b0a52637, < 39c0ceedd54557bdc1542de08d22b2ed33e534e4
Linux	Linux	5.17

References

Timeline

Published: Oct 18, 2026
Last Modified: Oct 21, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-98505?

In the Linux kernel, the following vulnerability has been resolved: mm/damon/vaddr: avoid hw-driven pte updates during damon_hugetlb_mkold() damon_hugetlb_mkold() reads the page table entry into a local variable, unsets the accessed bit in the variable, and updates the page table entry with the updated variable value. If hardware updates the same page table entry in parallel, the hw updates could be lost. For example, hardware-updated dirty bits might be lost. Avoid the parallel updates by clearing the page table entry when reading it together, using huge_ptep_get_and_clear(). If a parallel write to the memory is made after the clearing, the hw will see the page table entry is cleared, trigger page fault and wait until it is handled. The page fault handling will wait for damon_hugetlb_mkold() due to the page table lock. Because hugetlbfs is an in-memory file system and hugetlb pages cannot be reclaimed, no critical issue is expected to my best knowledge. But definitely this is a nasty bug that should be fixed sooner rather than later. The issue was discovered [1] by Sashiko.

How severe is CVE-2026-98505?

Severity scoring for CVE-2026-98505 is pending analysis. The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2026-98505?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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