# CVE-2026-53035: bpf, sockmap: Fix af_unix iter deadlock

> A deadlock in the Linux kernel's BPF sockmap implementation allows local attackers to cause a system hang via recursive locking.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Jun 2026
- **Updated:** 24 Jun 2026
- **Also known as:** BELL-CVE-2026-53035, DEBIAN-CVE-2026-53035, GHSA-9ppp-c797-fg56, ROOT-OS-DEBIAN-12-CVE-2026-53035, ROOT-OS-UBUNTU-2204-CVE-2026-53035, ROOT-OS-UBUNTU-2404-CVE-2026-53035, UBUNTU-CVE-2026-53035

## What is CVE-2026-53035?

CVE-2026-53035 is a medium-severity vulnerability in Linux kernel, published on 24 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

bpf, sockmap: Fix af_unix iter deadlock

bpf_iter_unix_seq_show() may deadlock when lock_sock_fast() takes the fast
path and the iter prog attempts to update a sockmap. Which ends up spinning
at sock_map_update_elem()'s bh_lock_sock():

WARNING: possible recursive locking detected
test_progs/1393 is trying to acquire lock:
ffff88811ec25f58 (slock-AF_UNIX){+...}-{3:3}, at: sock_map_update_elem+0xdb/0x1f0

but task is already holding lock:
ffff88811ec25f58 (slock-AF_UNIX){+...}-{3:3}, at: __lock_sock_fast+0x37/0xe0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(slock-AF_UNIX);
  lock(slock-AF_UNIX);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

4 locks held by test_progs/1393:
 #0: ffff88814b59c790 (&p->lock){+.+.}-{4:4}, at: bpf_seq_read+0x59/0x10d0
 #1: ffff88811ec25fd8 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: bpf_seq_read+0x42c/0x10d0
 #2: ffff88811ec25f58 (slock-AF_UNIX){+...}-{3:3}, at: __lock_sock_fast+0x37/0xe0
 #3: ffffffff85a6a7c0 (rcu_read_lock){....}-{1:3}, at: bpf_iter_run_prog+0x51d/0xb00

Call Trace:
 dump_stack_lvl+0x5d/0x80
 print_deadlock_bug.cold+0xc0/0xce
 __lock_acquire+0x130f/0x2590
 lock_acquire+0x14e/0x2b0
 _raw_spin_lock+0x30/0x40
 sock_map_update_elem+0xdb/0x1f0
 bpf_prog_2d0075e5d9b721cd_dump_unix+0x55/0x4f4
 bpf_iter_run_prog+0x5b9/0xb00
 bpf_iter_unix_seq_show+0x1f7/0x2e0
 bpf_seq_read+0x42c/0x10d0
 vfs_read+0x171/0xb20
 ksys_read+0xff/0x200
 do_syscall_64+0x6b/0x3a0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-53035?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53035?

Apply the vendor's patch.

## Is CVE-2026-53035 being exploited?

There is no known exploitation of CVE-2026-53035 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-2026-53035 and fix it if it is affected.

What it is: CVE-2026-53035 is a medium-severity vulnerability in Linux kernel, published on 24 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53035 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-2026-53035/ (Markdown: https://insights.sbomify.com/CVE-2026-53035/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53035
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53035
- OSV: https://osv.dev/vulnerability/CVE-2026-53035

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53035/
Summaries are generated and may contain mistakes; the official description above is the record.