# CVE-2024-56608: drm/amd/display: Fix out-of-bounds access in 'dcn21_link_encoder_create'

> An out-of-bounds access in the AMD display driver can cause a kernel crash, requiring a patch to prevent denial of service.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 27 Dec 2024
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-55205, BELL-CVE-2024-56608, DEBIAN-CVE-2024-56608, GHSA-h345-5w6p-mhwf, ROOT-OS-UBUNTU-2204-CVE-2024-56608, UBUNTU-CVE-2024-56608

## What is CVE-2024-56608?

CVE-2024-56608 is a high-severity memory corruption vulnerability in Linux kernel, published on 27 Dec 2024. 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:

drm/amd/display: Fix out-of-bounds access in 'dcn21_link_encoder_create'

An issue was identified in the dcn21_link_encoder_create function where
an out-of-bounds access could occur when the hpd_source index was used
to reference the link_enc_hpd_regs array. This array has a fixed size
and the index was not being checked against the array's bounds before
accessing it.

This fix adds a conditional check to ensure that the hpd_source index is
within the valid range of the link_enc_hpd_regs array. If the index is
out of bounds, the function now returns NULL to prevent undefined
behavior.

References:

[   65.920507] ------------[ cut here ]------------
[   65.920510] UBSAN: array-index-out-of-bounds in drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn21/dcn21_resource.c:1312:29
[   65.920519] index 7 is out of range for type 'dcn10_link_enc_hpd_registers [5]'
[   65.920523] CPU: 3 PID: 1178 Comm: modprobe Tainted: G           OE      6.8.0-cleanershaderfeatureresetasdntipmi200nv2132 #13
[   65.920525] Hardware name: AMD Majolica-RN/Majolica-RN, BIOS WMJ0429N_Weekly_20_04_2 04/29/2020
[   65.920527] Call Trace:
[   65.920529]  <TASK>
[   65.920532]  dump_stack_lvl+0x48/0x70
[   65.920541]  dump_stack+0x10/0x20
[   65.920543]  __ubsan_handle_out_of_bounds+0xa2/0xe0
[   65.920549]  dcn21_link_encoder_create+0xd9/0x140 [amdgpu]
[   65.921009]  link_create+0x6d3/0xed0 [amdgpu]
[   65.921355]  create_links+0x18a/0x4e0 [amdgpu]
[   65.921679]  dc_create+0x360/0x720 [amdgpu]
[   65.921999]  ? dmi_matches+0xa0/0x220
[   65.922004]  amdgpu_dm_init+0x2b6/0x2c90 [amdgpu]
[   65.922342]  ? console_unlock+0x77/0x120
[   65.922348]  ? dev_printk_emit+0x86/0xb0
[   65.922354]  dm_hw_init+0x15/0x40 [amdgpu]
[   65.922686]  amdgpu_device_init+0x26a8/0x33a0 [amdgpu]
[   65.922921]  amdgpu_driver_load_kms+0x1b/0xa0 [amdgpu]
[   65.923087]  amdgpu_pci_probe+0x1b7/0x630 [amdgpu]
[   65.923087]  local_pci_probe+0x4b/0xb0
[   65.923087]  pci_device_probe+0xc8/0x280
[   65.923087]  really_probe+0x187/0x300
[   65.923087]  __driver_probe_device+0x85/0x130
[   65.923087]  driver_probe_device+0x24/0x110
[   65.923087]  __driver_attach+0xac/0x1d0
[   65.923087]  ? __pfx___driver_attach+0x10/0x10
[   65.923087]  bus_for_each_dev+0x7d/0xd0
[   65.923087]  driver_attach+0x1e/0x30
[   65.923087]  bus_add_driver+0xf2/0x200
[   65.923087]  driver_register+0x64/0x130
[   65.923087]  ? __pfx_amdgpu_init+0x10/0x10 [amdgpu]
[   65.923087]  __pci_register_driver+0x61/0x70
[   65.923087]  amdgpu_init+0x7d/0xff0 [amdgpu]
[   65.923087]  do_one_initcall+0x49/0x310
[   65.923087]  ? kmalloc_trace+0x136/0x360
[   65.923087]  do_init_module+0x6a/0x270
[   65.923087]  load_module+0x1fce/0x23a0
[   65.923087]  init_module_from_file+0x9c/0xe0
[   65.923087]  ? init_module_from_file+0x9c/0xe0
[   65.923087]  idempotent_init_module+0x179/0x230
[   65.923087]  __x64_sys_finit_module+0x5d/0xa0
[   65.923087]  do_syscall_64+0x76/0x120
[   65.923087]  entry_SYSCALL_64_after_hwframe+0x6e/0x76
[   65.923087] RIP: 0033:0x7f2d80f1e88d
[   65.923087] Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 b5 0f 00 f7 d8 64 89 01 48
[   65.923087] RSP: 002b:00007ffc7bc1aa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[   65.923087] RAX: ffffffffffffffda RBX: 0000564c9c1db130 RCX: 00007f2d80f1e88d
[   65.923087] RDX: 0000000000000000 RSI: 0000564c9c1e5480 RDI: 000000000000000f
[   65.923087] RBP: 0000000000040000 R08: 0000000000000000 R09: 0000000000000002
[   65.923087] R10: 000000000000000f R11: 0000000000000246 R12: 0000564c9c1e5480
[   65.923087] R13: 0000564c9c1db260 R14: 0000000000000000 R15: 0000564c9c1e54b0
[   65.923087]  </TASK>
[   65.923927] ---[ end trace ]---

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2024-56608?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-56608?

Apply the vendor's patch.

## Is CVE-2024-56608 being exploited?

There is no known exploitation of CVE-2024-56608 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-2024-56608 and fix it if it is affected.

What it is: CVE-2024-56608 is a high-severity memory corruption vulnerability in Linux kernel, published on 27 Dec 2024. 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-2024-56608 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-2024-56608/ (Markdown: https://insights.sbomify.com/CVE-2024-56608/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-56608
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-56608
- OSV: https://osv.dev/vulnerability/CVE-2024-56608

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-56608/
Summaries are generated and may contain mistakes; the official description above is the record.
