🛡️ CVE-2025-40028 — kernel

🟠 CVSS 7.8 — High ✅ No Known Exploit NVD
7.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

binder: fix double-free in dbitmap

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().

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Affected software

CVE-2025-40028 is recorded against 2 packages.

  • kernel (from 6.17.0 up to 6.17.2)
  • unknown

Timeline and source

Published on 28 October 2025 and last revised on 6 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

CVE-2025-40028 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity High
CVSS Score 7.8
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-10-28
Updated 2026-08-12
Modified 2026-08-06
Fix URL N/A

Affected Packages

Software From version Fixed in
kernel 6.17.0 6.17.2
unknown — —

Similar Threats

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