# CVE-2024-53177: smb: prevent use-after-free due to open_cached_dir error paths

> A use-after-free vulnerability in the Linux kernel SMB client allows attackers to cause denial of service or potentially execute code via race conditions during lease handling.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Dec 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-53177, DEBIAN-CVE-2024-53177, GHSA-5hh7-6vv2-v2hg, ROOT-OS-DEBIAN-11-CVE-2024-53177, ROOT-OS-DEBIAN-12-CVE-2024-53177, ROOT-OS-UBUNTU-2204-CVE-2024-53177, UBUNTU-CVE-2024-53177

## What is CVE-2024-53177?

CVE-2024-53177 is a critical use after free vulnerability in Linux kernel, published on 27 Dec 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

smb: prevent use-after-free due to open_cached_dir error paths

If open_cached_dir() encounters an error parsing the lease from the
server, the error handling may race with receiving a lease break,
resulting in open_cached_dir() freeing the cfid while the queued work is
pending.

Update open_cached_dir() to drop refs rather than directly freeing the
cfid.

Have cached_dir_lease_break(), cfids_laundromat_worker(), and
invalidate_all_cached_dirs() clear has_lease immediately while still
holding cfids->cfid_list_lock, and then use this to also simplify the
reference counting in cfids_laundromat_worker() and
invalidate_all_cached_dirs().

Fixes this KASAN splat (which manually injects an error and lease break
in open_cached_dir()):

==================================================================
BUG: KASAN: slab-use-after-free in smb2_cached_lease_break+0x27/0xb0
Read of size 8 at addr ffff88811cc24c10 by task kworker/3:1/65

CPU: 3 UID: 0 PID: 65 Comm: kworker/3:1 Not tainted 6.12.0-rc6-g255cf264e6e5-dirty #87
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
Workqueue: cifsiod smb2_cached_lease_break
Call Trace:
 <TASK>
 dump_stack_lvl+0x77/0xb0
 print_report+0xce/0x660
 kasan_report+0xd3/0x110
 smb2_cached_lease_break+0x27/0xb0
 process_one_work+0x50a/0xc50
 worker_thread+0x2ba/0x530
 kthread+0x17c/0x1c0
 ret_from_fork+0x34/0x60
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 2464:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 __kasan_kmalloc+0xaa/0xb0
 open_cached_dir+0xa7d/0x1fb0
 smb2_query_path_info+0x43c/0x6e0
 cifs_get_fattr+0x346/0xf10
 cifs_get_inode_info+0x157/0x210
 cifs_revalidate_dentry_attr+0x2d1/0x460
 cifs_getattr+0x173/0x470
 vfs_statx_path+0x10f/0x160
 vfs_statx+0xe9/0x150
 vfs_fstatat+0x5e/0xc0
 __do_sys_newfstatat+0x91/0xf0
 do_syscall_64+0x95/0x1a0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Freed by task 2464:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 kasan_save_free_info+0x3b/0x60
 __kasan_slab_free+0x51/0x70
 kfree+0x174/0x520
 open_cached_dir+0x97f/0x1fb0
 smb2_query_path_info+0x43c/0x6e0
 cifs_get_fattr+0x346/0xf10
 cifs_get_inode_info+0x157/0x210
 cifs_revalidate_dentry_attr+0x2d1/0x460
 cifs_getattr+0x173/0x470
 vfs_statx_path+0x10f/0x160
 vfs_statx+0xe9/0x150
 vfs_fstatat+0x5e/0xc0
 __do_sys_newfstatat+0x91/0xf0
 do_syscall_64+0x95/0x1a0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Last potentially related work creation:
 kasan_save_stack+0x33/0x60
 __kasan_record_aux_stack+0xad/0xc0
 insert_work+0x32/0x100
 __queue_work+0x5c9/0x870
 queue_work_on+0x82/0x90
 open_cached_dir+0x1369/0x1fb0
 smb2_query_path_info+0x43c/0x6e0
 cifs_get_fattr+0x346/0xf10
 cifs_get_inode_info+0x157/0x210
 cifs_revalidate_dentry_attr+0x2d1/0x460
 cifs_getattr+0x173/0x470
 vfs_statx_path+0x10f/0x160
 vfs_statx+0xe9/0x150
 vfs_fstatat+0x5e/0xc0
 __do_sys_newfstatat+0x91/0xf0
 do_syscall_64+0x95/0x1a0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

The buggy address belongs to the object at ffff88811cc24c00
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 16 bytes inside of
 freed 1024-byte region [ffff88811cc24c00, ffff88811cc25000)

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2024-53177?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-53177?

Apply the vendor's patch.

## Is CVE-2024-53177 being exploited?

There is no known exploitation of CVE-2024-53177 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-53177 and fix it if it is affected.

What it is: CVE-2024-53177 is a critical use after free vulnerability in Linux kernel, published on 27 Dec 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-53177 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-53177/ (Markdown: https://insights.sbomify.com/CVE-2024-53177/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-53177
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-53177
- OSV: https://osv.dev/vulnerability/CVE-2024-53177

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-53177/
Summaries are generated and may contain mistakes; the official description above is the record.