CVE-2026-52905: mm/damon/core: disallow non-power of two min_region_sz on damon_start()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-09 · updated 2026-07-23
Weakness: CWE-1284

Description

In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: disallow non-power of two min_region_sz on damon_start() Commit d8f867fa0825 ("mm/damon: add damon_ctx->min_sz_region") introduced a bug that allows unaligned DAMON region address ranges. Commit c80f46ac228b ("mm/damon/core: disallow non-power of two min_region_sz") fixed it, but only for damon_commit_ctx() use case. Still, DAMON sysfs interface can emit non-power of two min_region_sz via damon_start(). Fix the path by adding the is_power_of_2() check on damon_start(). The issue was discovered by sashiko [1].

Affected products

Linux kernel: from 6.18 before 6.18.30; from 6.19 before 7.0.4 — fixed in 6.18.30, 7.0.4

How to fix

Upgrade to a fixed version: Linux kernel 6.18.30, 7.0.4. Check the vendor advisory for mitigations.

References

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