{ "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" } } } }