CVE-2026-64458
Low risk· EPSS 8%Exploitation Probability (EPSS)
Low risk8th percentile - higher than 8% of all known CVEs
Summary
A vulnerability in the Linux kernel's DAMON module was found in the damon_hot_score() function, which mishandles extreme monitoring interval values (zero or too high). Setting a zero sampling interval causes a divide-by-zero error, while a zero aggregation interval returns an incorrect value, also leading to division by zero. An excessively high aggregation interval can cause an out-of-bounds array access, resulting in memory corruption.
Risk Assessment
The vulnerability allows a local attacker with sysfs write permissions to crash the system (Oops) by setting extreme DAMON monitoring intervals. This can lead to a denial of service (DoS) at the kernel level.
Recommendation
Apply the Linux kernel patch that fixes the handling of extreme intervals in damon_hot_score() and damon_max_nr_accesses() immediately. Upgrading to a patched kernel version is recommended.
Other vulnerabilities in Linux kernel
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- CVE-2026-99258Unknown
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- CVE-2026-99257Unknown
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- CVE-2026-99256Unknown
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- CVE-2026-99251Unknown
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- CVE-2026-99250Unknown
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- CVE-2026-99247Unknown
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Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: mm/damon/ops-common: handle extreme intervals in damon_hot_score() Fix three issues in damon_hot_score() that comes from wrong handling of extreme (zero or too high) monitoring intervals user setup. When the user sets sampling interval zero, damon_max_nr_accesses(), which is called from damon_hot_score(), causes a divide-by-zero. Needless to say, it is a problem. When the user sets the aggregation interval zero, the function returns zero. It is wrong, since the real maximum nr_acceses in the setup should be one. Worse yet, it can cause another divide-by-zero from its caller, damon_hot_score(), since it uses damon_max_nr_accesses() return value as a denominator. When the user sets the aggregation interval very high, damon_hot_score() could return a value out of [0, DAMOS_MAX_SCORE] range. Since the return value is used as an index to the regions_score_histogram array, which is DAMOS_MAX_SCORE+1 size, it causes out of bounds array access. The issues can be relatively easily reproduced like below. The sysfs write permission is required, though. # ./damo start --damos_action lru_prio --damos_quota_space 100M \ --damos_quota_interval 1s # cd /sys/kernel/mm/damon/admin/kdamonds/0 # echo 0 > contexts/0/monitoring_attrs/intervals/sample_us # echo 0 > contexts/0/monitoring_attrs/intervals/aggr_us # echo commit > state # dmesg [...] [ 131.329762] Oops: divide error: 0000 [#1] SMP NOPTI [...] [ 131.336089] RIP: 0010:damon_hot_score+0x27/0xd0 [...] Fix the divide-by-zero intervals problems by explicitly handling the zero intervals in damon_max_nr_accesses(). Fix the out-of-bound array access by applying [0, DAMOS_MAX_SCORE] bounds before returning from damon_hot_score(). The issue was discovered [1] by Sashiko.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

