Kernel memory corruption via delayed kobject release
Published Jul 24, 2026 · Updated Jul 24, 2026
Use-after-free in Linux Kernel DAMON sysfs allows local users to corrupt kernel memory by refreshing tried-region directories. damon_sysfs_scheme_regions_rm_dirs() drops kobject references but leaves region nodes linked until delayed release callbacks, so refresh can rebuild the list around objects pending deallocation. Reachability requires privileged DAMON sysfs access on a kernel built with CONFIG_DEBUG_KOBJECT_RELEASE; repeated refreshes can corrupt the list and trigger a refcount underflow or use-after-free.
Summary
What happened
Use-after-free in Linux Kernel DAMON sysfs allows local users to corrupt kernel memory by refreshing tried-region directories. damon_sysfs_scheme_regions_rm_dirs() drops kobject references but leaves region nodes linked until delayed release callbacks, so refresh can rebuild the list around objects pending deallocation. Reachability requires privileged DAMON sysfs access on a kernel built with CONFIG_DEBUG_KOBJECT_RELEASE; repeated refreshes can corrupt the list and trigger a refcount underflow or use-after-free.
The record
- CVE
- CVE-2026-64239
- Published
- Jul 24, 2026
- Updated
- Jul 24, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-416, T1499.004
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Jul 24, 2026CVE publishedPublication date reported by the CVE source.
- Jul 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.2
- Affected versionversion=9277d0367ba18ef4bb98bafb1209e715844cdf7e <0ba6c05156d9ff9fc6ca22b7690e2eec9eca66f7
- Affected versionversion=9277d0367ba18ef4bb98bafb1209e715844cdf7e <2c33177023c92e76806c535ddbffaa3d3fc37777
- Affected versionversion=9277d0367ba18ef4bb98bafb1209e715844cdf7e <441f92f7d386b85bad16de49db95a307cba048a2
- Affected versionversion=9277d0367ba18ef4bb98bafb1209e715844cdf7e <a5fa42214de55e43d165144727ce9facb9fc6b08
- Affected versionversion=9277d0367ba18ef4bb98bafb1209e715844cdf7e <c0e37017a452addec873865c94cf7a665663a9b2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Linux DAMON sysfs tried-region refresh reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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