CVE Catalog

CVE-2026-74645

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel's DAMON_LRU_SORT module, there is a division by zero vulnerability when the active_mem_bp parameter is set to a value greater than 10000. The target value for cold memory is calculated as '10000 - active_mem_bp + 2', which becomes zero for 10002, causing a divide error. The fix returns an error when starting DAMON with >10000.

Risk Assessment

The vulnerability can cause a kernel oops and potentially a denial of service. It requires write permission to module parameters, but the consequences are severe.

Recommendation

Apply the kernel patch that prevents setting active_mem_bp above 10000. Also restrict permissions to modify module parameters.

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: mm/damon/lru_sort: error out for >10000 active_mem_bp damos_quota_score() can trigger division by zero if the target value is zero. DAMON_LRU_SORT lets users set the target value for the hot memory scheme via active_mem_bp parameter. It avoids setting it as the target value if the parameter value is zero. However, it also sets the cold memory scheme with a target value that is calculated as '10000 - active_mem_bp + 2'. Hence, if a user sets active_mem_bp 10002, the cold memory scheme's quota goal target value can be zero. As a result, division by zero can be triggered. Fix by returning an error when the user tries to start DAMON with >10000 active_mem_bp parameter value. It makes no sense to set active_mem_bp with 10002. It also requires module parameters write permission to reproduce the issue. That said, the consequence is quite bad. One reliable way to reproduce the issue is like below: # cd /sys/module/damon_lru_sort/parameters # echo 1000 > wmarks_high # echo 995 > wmarks_mid # echo 0 > wmarks_low # echo 10002 > active_mem_bp # echo Y > enabled # dmesg -w [...] [ 597.421247] Oops: divide error: 0000 [#1] SMP NOPTI [ 597.428848] RIP: 0010:damos_quota_score+0x6f/0x480 This issue was discovered [1] by Sashiko.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS