# CVE-2026-31510: Bluetooth: L2CAP: Fix null-ptr-deref on l2cap_sock_ready_cb

> A null pointer dereference in the Linux kernel Bluetooth L2CAP module allows attackers to cause a system crash via crafted Bluetooth packets.

- **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:** 22 Apr 2026
- **Updated:** 11 May 2026
- **Also known as:** AZL-83267, BELL-CVE-2026-31510, DEBIAN-CVE-2026-31510, GHSA-rv4p-485x-2f9c, ROOT-OS-DEBIAN-11-CVE-2026-31510, ROOT-OS-DEBIAN-12-CVE-2026-31510, ROOT-OS-DEBIAN-13-CVE-2026-31510, ROOT-OS-UBUNTU-2204-CVE-2026-31510, ROOT-OS-UBUNTU-2404-CVE-2026-31510, UBUNTU-CVE-2026-31510

## What is CVE-2026-31510?

CVE-2026-31510 is a medium-severity vulnerability in Linux kernel, published on 22 Apr 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:

Bluetooth: L2CAP: Fix null-ptr-deref on l2cap_sock_ready_cb

Before using sk pointer, check if it is null.

Fix the following:

 KASAN: null-ptr-deref in range [0x0000000000000260-0x0000000000000267]
 CPU: 0 UID: 0 PID: 5985 Comm: kworker/0:5 Not tainted 7.0.0-rc4-00029-ga989fde763f4 #1 PREEMPT(full)
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-9.fc43 06/10/2025
 Workqueue: events l2cap_info_timeout
 RIP: 0010:kasan_byte_accessible+0x12/0x30
 Code: 79 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 c1 ef 03 48 b8 00 00 00 00 00 fc ff df <0f> b6 04 07 3c 08 0f 92 c0 c3 cc cce
 veth0_macvtap: entered promiscuous mode
 RSP: 0018:ffffc90006e0f808 EFLAGS: 00010202
 RAX: dffffc0000000000 RBX: ffffffff89746018 RCX: 0000000080000001
 RDX: 0000000000000000 RSI: ffffffff89746018 RDI: 000000000000004c
 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
 R10: dffffc0000000000 R11: ffffffff8aae3e70 R12: 0000000000000000
 R13: 0000000000000260 R14: 0000000000000260 R15: 0000000000000001
 FS:  0000000000000000(0000) GS:ffff8880983c2000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00005582615a5008 CR3: 000000007007e000 CR4: 0000000000752ef0
 PKRU: 55555554
 Call Trace:
  <TASK>
  __kasan_check_byte+0x12/0x40
  lock_acquire+0x79/0x2e0
  lock_sock_nested+0x48/0x100
  ? l2cap_sock_ready_cb+0x46/0x160
  l2cap_sock_ready_cb+0x46/0x160
  l2cap_conn_start+0x779/0xff0
  ? __pfx_l2cap_conn_start+0x10/0x10
  ? l2cap_info_timeout+0x60/0xa0
  ? __pfx___mutex_lock+0x10/0x10
  l2cap_info_timeout+0x68/0xa0
  ? process_scheduled_works+0xa8d/0x18c0
  process_scheduled_works+0xb6e/0x18c0
  ? __pfx_process_scheduled_works+0x10/0x10
  ? assign_work+0x3d5/0x5e0
  worker_thread+0xa53/0xfc0
  kthread+0x388/0x470
  ? __pfx_worker_thread+0x10/0x10
  ? __pfx_kthread+0x10/0x10
  ret_from_fork+0x51e/0xb90
  ? __pfx_ret_from_fork+0x10/0x10
 veth1_macvtap: entered promiscuous mode
  ? __switch_to+0xc7d/0x1450
  ? __pfx_kthread+0x10/0x10
  ret_from_fork_asm+0x1a/0x30
  </TASK>
 Modules linked in:
 ---[ end trace 0000000000000000 ]---
 batman_adv: batadv0: Interface activated: batadv_slave_0
 batman_adv: batadv0: Interface activated: batadv_slave_1
 netdevsim netdevsim7 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
 netdevsim netdevsim7 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
 netdevsim netdevsim7 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
 netdevsim netdevsim7 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
 RIP: 0010:kasan_byte_accessible+0x12/0x30
 Code: 79 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 c1 ef 03 48 b8 00 00 00 00 00 fc ff df <0f> b6 04 07 3c 08 0f 92 c0 c3 cc cce
 ieee80211 phy39: Selected rate control algorithm 'minstrel_ht'
 RSP: 0018:ffffc90006e0f808 EFLAGS: 00010202
 RAX: dffffc0000000000 RBX: ffffffff89746018 RCX: 0000000080000001
 RDX: 0000000000000000 RSI: ffffffff89746018 RDI: 000000000000004c
 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
 R10: dffffc0000000000 R11: ffffffff8aae3e70 R12: 0000000000000000
 R13: 0000000000000260 R14: 0000000000000260 R15: 0000000000000001
 FS:  0000000000000000(0000) GS:ffff8880983c2000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f7e16139e9c CR3: 000000000e74e000 CR4: 0000000000752ef0
 PKRU: 55555554
 Kernel panic - not syncing: Fatal exception

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-31510?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31510?

Apply the vendor's patch.

## Is CVE-2026-31510 being exploited?

There is no known exploitation of CVE-2026-31510 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-2026-31510 and fix it if it is affected.

What it is: CVE-2026-31510 is a medium-severity vulnerability in Linux kernel, published on 22 Apr 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-2026-31510 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-2026-31510/ (Markdown: https://insights.sbomify.com/CVE-2026-31510/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31510
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31510
- OSV: https://osv.dev/vulnerability/CVE-2026-31510

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31510/
Summaries are generated and may contain mistakes; the official description above is the record.