CVE-2025-40028

CVE-2025-40028 is a security vulnerability that is still awaiting full analysis and scoring. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: binder: fix double-free in dbitmap A process might fail to allocate a new bitmap when trying to expand its proc->dmap. In that case, dbitmap_grow() fails and frees the old bitmap via dbitmap_free(). However, the driver calls dbitmap_free() again when the same process terminates, leading to a double-free error: ================================================================== BUG: KASAN: double-free in binder_proc_dec_tmpref+0x2e0/0x55c Free of addr ffff00000b7c1420 by task kworker/9:1/209 CPU: 9 UID: 0 PID: 209 Comm: kworker/9:1 Not tainted 6.17.0-rc6-dirty #5 PREEMPT Hardware name: linux,dummy-virt (DT) Workqueue: events binder_deferred_func Call trace: kfree+0x164/0x31c binder_proc_dec_tmpref+0x2e0/0x55c binder_deferred_func+0xc24/0x1120 process_one_work+0x520/0xba4 [...] Allocated by task 448: __kmalloc_noprof+0x178/0x3c0 bitmap_zalloc+0x24/0x30 binder_open+0x14c/0xc10 [...] Freed by task 449: kfree+0x184/0x31c binder_inc_ref_for_node+0xb44/0xe44 binder_transaction+0x29b4/0x7fbc binder_thread_write+0x1708/0x442c binder_ioctl+0x1b50/0x2900 [...] ================================================================== Fix this issue by marking proc->map NULL in dbitmap_free().

Frequently asked questions

What is CVE-2025-40028?
In the Linux kernel, the following vulnerability has been resolved: binder: fix double-free in dbitmap A process might fail to allocate a new bitmap when trying to expand its proc->dmap. In that case, dbitmap_grow() fails and frees the old bitmap via dbitmap_free(). However, the driver calls dbitmap_free() again when the same process terminates, leading to a double-free error: ================================================================== BUG: KASAN: double-free in binder_proc_dec_tmpref+0x2e0/0x55c Free of addr ffff00000b7c1420 by task kworker/9:1/209 CPU: 9 UID: 0 PID: 209 Comm: kworker/9:1 Not tainted 6.17.0-rc6-dirty #5 PREEMPT Hardware name: linux,dummy-virt (DT) Workqueue: events binder_deferred_func Call trace: kfree+0x164/0x31c binder_proc_dec_tmpref+0x2e0/0x55c binder_deferred_func+0xc24/0x1120 process_one_work+0x520/0xba4 [...] Allocated by task 448: __kmalloc_noprof+0x178/0x3c0 bitmap_zalloc+0x24/0x30 binder_open+0x14c/0xc10 [...] Freed by task 449: kfree+0x184/0x31c binder_inc_ref_for_node+0xb44/0xe44 binder_transaction+0x29b4/0x7fbc binder_thread_write+0x1708/0x442c binder_ioctl+0x1b50/0x2900 [...] ================================================================== Fix this issue by marking proc->map NULL in dbitmap_free().
Is CVE-2025-40028 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-40028?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-40028 have an EU (EUVD) identifier?
Yes. CVE-2025-40028 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-36439.
When was CVE-2025-40028 published?
CVE-2025-40028 was published on 2025-10-28 and last updated on 2026-06-17.

References