GHSA-GQJW-3MH5-7PR5
Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31In the Linux kernel, the following vulnerability has been resolved:
binder: fix UAF in binder_thread_release()
When a thread exits, binder_thread_release() walks its transaction stack to clear the t->from and t->to_proc that correspond with the exiting thread. However, a process dying in parallel might attempt to kfree some of these transactions. And if one of them has no associated t->to_proc, the t->to_proc->inner_lock will not be acquired.
This means that transaction accesses in binder_thread_release() after t->to_proc has been cleared might race with binder_free_transaction() and cause a use-after-free error as reported by KASAN:
================================================================== BUG: KASAN: slab-use-after-free in binder_thread_release+0x5d0/0x798 Write of size 8 at addr ffff000016627500 by task X/715
CPU: 17 UID: 0 PID: 715 Comm: X Not tainted 7.1.0-rc5-00149-g8fde5d1d47f6 #30 PREEMPT Hardware name: linux,dummy-virt (DT) Call trace: binder_thread_release+0x5d0/0x798 binder_ioctl+0x12c0/0x299c [...]
Allocated by task 717 on cpu 18 at 67.267803s: __kasan_kmalloc+0xa0/0xbc __kmalloc_cache_noprof+0x174/0x444 binder_transaction+0x554/0x8150 binder_thread_write+0xa30/0x4354 binder_ioctl+0x20f0/0x299c [...]
Freed by task 202 on cpu 18 at 90.416221s: __kasan_slab_free+0x58/0x80 kfree+0x1a0/0x4a4 binder_free_transaction+0x150/0x294 binder_send_failed_reply+0x398/0x6d8 binder_release_work+0x3e4/0x4ec binder_deferred_func+0xbd8/0x104c [...] ==================================================================
In order to avoid this, make sure that binder_free_transaction() reads the t->to_proc under the transaction lock. This will serialize the transaction release with the accesses in binder_thread_release(). Plus, it matches the documented locking rules for @to_proc.
{
"affected": [],
"aliases": [
"CVE-2026-64469"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-25T10:17:32Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbinder: fix UAF in binder_thread_release()\n\nWhen a thread exits, binder_thread_release() walks its transaction stack\nto clear the t-\u003efrom and t-\u003eto_proc that correspond with the exiting\nthread. However, a process dying in parallel might attempt to kfree some\nof these transactions. And if one of them has no associated t-\u003eto_proc,\nthe t-\u003eto_proc-\u003einner_lock will not be acquired.\n\nThis means that transaction accesses in binder_thread_release() after\nt-\u003eto_proc has been cleared might race with binder_free_transaction()\nand cause a use-after-free error as reported by KASAN:\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in binder_thread_release+0x5d0/0x798\n Write of size 8 at addr ffff000016627500 by task X/715\n\n CPU: 17 UID: 0 PID: 715 Comm: X Not tainted 7.1.0-rc5-00149-g8fde5d1d47f6 #30 PREEMPT\n Hardware name: linux,dummy-virt (DT)\n Call trace:\n binder_thread_release+0x5d0/0x798\n binder_ioctl+0x12c0/0x299c\n [...]\n\n Allocated by task 717 on cpu 18 at 67.267803s:\n __kasan_kmalloc+0xa0/0xbc\n __kmalloc_cache_noprof+0x174/0x444\n binder_transaction+0x554/0x8150\n binder_thread_write+0xa30/0x4354\n binder_ioctl+0x20f0/0x299c\n [...]\n\n Freed by task 202 on cpu 18 at 90.416221s:\n __kasan_slab_free+0x58/0x80\n kfree+0x1a0/0x4a4\n binder_free_transaction+0x150/0x294\n binder_send_failed_reply+0x398/0x6d8\n binder_release_work+0x3e4/0x4ec\n binder_deferred_func+0xbd8/0x104c\n [...]\n ==================================================================\n\nIn order to avoid this, make sure that binder_free_transaction() reads\nthe t-\u003eto_proc under the transaction lock. This will serialize the\ntransaction release with the accesses in binder_thread_release(). Plus,\nit matches the documented locking rules for @to_proc.",
"id": "GHSA-gqjw-3mh5-7pr5",
"modified": "2026-07-25T12:31:37Z",
"published": "2026-07-25T12:31:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64469"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/114a116aaa5f0295376cdf12da743c5bce3b20ce"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1f96f8c0a6ed4f6d01d3dd29ad0cbf08dde96082"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/38e1a71728e5795b670cc159c18e286a40aeebb4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/df1a17abba8d6fac5f965adcb8113ceace6e4949"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e63032dc715026a96bcaa13d375a8e15c91caa84"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ea02df466df60ecd758eb3b4df3f0cadc5c886ce"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ef5439ba5b9ac93349f5df12ef88b42a0ce26340"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/faa070c7ad8ba25dcd0b12d7cdbb419e336f5391"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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