{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64073","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.031Z","datePublished":"2026-07-19T15:39:48.463Z","dateUpdated":"2026-08-05T12:38:54.369Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:38:54.369Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nirq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT\n\nOn PREEMPT_RT, non-HARD irq_work runs in per-CPU kthreads via\nrun_irq_workd(), so irq_work_sync() uses rcuwait() to wait for BUSY==0.\n\nAfter irq_work_single() clears BUSY via atomic_cmpxchg(), it still\ndereferences @work for irq_work_is_hard() and rcuwait_wake_up().\n\nAn irq_work_sync() caller on another CPU that enters after BUSY is cleared\ncan observe BUSY==0 immediately, return, and free the work before those\naccesses complete — causing a use-after-free.\n\nFix this by wrapping run_irq_workd() in guard(rcu)() so that the entire\nirq_work_single() execution is within an RCU read-side critical\nsection. Then add synchronize_rcu() in irq_work_sync() after\nrcuwait_wait_event() to ensure the caller waits for the RCU grace period\nbefore returning, preventing premature frees."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires reaching irq_work_sync() teardown paths via local syscalls (e.g. perf_event_open/close, bpf map teardown) that queue non-HARD irq_work on PREEMPT_RT; there is no direct network packet or remote-protocol entry point into irq_work.c.\nAC:L - The bug is a cross-CPU race where irq_work_sync() returns after BUSY is cleared while irq_work_single() still dereferences the work; an attacker can control both sides by concurrently closing/freeing a subsystem object and driving irq_work_queue() from another thread/CPU (e.g. perf fasync wakeup vs. close).\nPR:L - Unprivileged local users can reach vulnerable teardown via perf_event_open/close on per-task events (exclude_kernel=1, default paranoid=2) and via bpf() ringbuf/map cleanup when CAP_BPF is available in a user namespace; no init-namespace root is required for the highest-impact paths.\nUI:N - Exploitation is driven entirely by the attacker's own syscalls and threading; no victim interaction such as opening files or mounting filesystems is needed.\nS:U - Successful exploitation corrupts or reads kernel memory and can yield local privilege escalation within the same kernel security authority; it does not inherently cross a VM/host, IOMMU, or container boundary by itself.\nC:H - This is a kernel heap use-after-free: irq_work_single() dereferences a freed irq_work embedded in structures like perf_event or bpf_ringbuf, enabling arbitrary kernel memory disclosure through heap reuse and controlled reads of stale object fields.\nI:H - The UAF permits attacker-controlled reallocation of the freed irq_work container object, providing a standard kernel heap corruption primitive that can be developed into arbitrary write or control-flow hijack, not merely a bounded modification.\nA:H - Use-after-free in irq_work_single() can immediately fault or panic the kernel during post-BUSY dereferences, and repeated triggering via perf/BPF open-close races can cause persistent denial of service on PREEMPT_RT systems."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/irq_work.c"],"versions":[{"version":"810979682ccc98dbd83f341c18a2e556c30a7164","lessThan":"2dc79362302922cb18f35e262712b5e58de65442","status":"affected","versionType":"git"},{"version":"810979682ccc98dbd83f341c18a2e556c30a7164","lessThan":"eef4f71b46a9929ac33e968538c9dd5d96a02460","status":"affected","versionType":"git"},{"version":"810979682ccc98dbd83f341c18a2e556c30a7164","lessThan":"684a78183c54c23e70d1cba320f7fc184604210b","status":"affected","versionType":"git"},{"version":"810979682ccc98dbd83f341c18a2e556c30a7164","lessThan":"18c0456ea2615b1a743a6db739c74411c3b42bc6","status":"affected","versionType":"git"},{"version":"810979682ccc98dbd83f341c18a2e556c30a7164","lessThan":"81b582784518196eff1050212a046bc29d3a05dd","status":"affected","versionType":"git"},{"version":"810979682ccc98dbd83f341c18a2e556c30a7164","lessThan":"91840be8f710370607f949a627e070896faeddb8","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/irq_work.c"],"versions":[{"version":"5.16","status":"affected"},{"version":"0","lessThan":"5.16","status":"unaffected","versionType":"semver"},{"version":"6.1.175","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.142","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.92","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.34","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.11","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.6.142"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.12.92"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/2dc79362302922cb18f35e262712b5e58de65442"},{"url":"https://git.kernel.org/stable/c/eef4f71b46a9929ac33e968538c9dd5d96a02460"},{"url":"https://git.kernel.org/stable/c/684a78183c54c23e70d1cba320f7fc184604210b"},{"url":"https://git.kernel.org/stable/c/18c0456ea2615b1a743a6db739c74411c3b42bc6"},{"url":"https://git.kernel.org/stable/c/81b582784518196eff1050212a046bc29d3a05dd"},{"url":"https://git.kernel.org/stable/c/91840be8f710370607f949a627e070896faeddb8"}],"title":"irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT","x_generator":{"engine":"bippy-1.2.0"}}}}