GHSA-45WG-MG8V-JX77
Vulnerability from github – Published: 2026-09-17 18:32 – Updated: 2026-09-17 18:32In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix use-after-free on mm_struct in bpf_find_vma()
bpf_find_vma() reads task->mm and calls mmap_read_trylock(mm) without holding a reference on the mm. On a foreign task, a concurrent exit_mm() can free the mm_struct between the lockless read and the trylock, resulting in a use-after-free. mm_struct is not SLAB_TYPESAFE_BY_RCU.
For the current task, task->mm is stable. For a foreign task, pin the mm under task->alloc_lock and release it with mmput_async(), mirroring commit d8e27d2d22b6 ("bpf: fix mm lifecycle in open-coded task_vma iterator"). Use spin_trylock() instead of get_task_mm() so BPF context does not block on alloc_lock. Reject irqs-disabled contexts and !CONFIG_MMU on the foreign-task path because dropping the mm reference is not safe there.
Race:
CPU0 (BPF program) CPU1 (exiting task) ============================ ========================== bpf_find_vma(foreign_task): mm = task->mm exit_mm(): task->mm = NULL mmput(mm) -> frees mm_struct mmap_read_trylock(mm) // UAF on mm
{
"affected": [],
"aliases": [
"CVE-2026-93137"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-17T17:18:08Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix use-after-free on mm_struct in bpf_find_vma()\n\nbpf_find_vma() reads task-\u003emm and calls mmap_read_trylock(mm) without\nholding a reference on the mm. On a foreign task, a concurrent exit_mm()\ncan free the mm_struct between the lockless read and the trylock,\nresulting in a use-after-free. mm_struct is not SLAB_TYPESAFE_BY_RCU.\n\nFor the current task, task-\u003emm is stable. For a foreign task, pin the mm\nunder task-\u003ealloc_lock and release it with mmput_async(), mirroring commit\nd8e27d2d22b6 (\"bpf: fix mm lifecycle in open-coded task_vma iterator\").\nUse spin_trylock() instead of get_task_mm() so BPF context does not block\non alloc_lock. Reject irqs-disabled contexts and !CONFIG_MMU on the\nforeign-task path because dropping the mm reference is not safe there.\n\nRace:\n\n CPU0 (BPF program) CPU1 (exiting task)\n ============================ ==========================\n bpf_find_vma(foreign_task):\n mm = task-\u003emm\n exit_mm():\n task-\u003emm = NULL\n mmput(mm) -\u003e frees mm_struct\n mmap_read_trylock(mm)\n // UAF on mm",
"id": "GHSA-45wg-mg8v-jx77",
"modified": "2026-09-17T18:32:11Z",
"published": "2026-09-17T18:32:11Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93137"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2b2a903bee56d312539046d9defa8023eec94760"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/47b079e2117a2ee52e21f8b72935900c702fc0b5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/86d54cf069fc5ae2e111c87933bebf6eb527978e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8e1101fc4118019a69c96ced4aec93164f89cbd5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c7ad910e987008e125eeff448892e86852173384"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/db347840d6b6ee9bb9b8e4a985d4b4419f9f3200"
}
],
"schema_version": "1.4.0",
"severity": []
}
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