Description
In the Linux kernel, the following vulnerability has been resolved:
erofs: fix wrong kunmap when using LZMA on HIGHMEM platforms
As the call trace shown, the root cause is kunmap incorrect pages:
BUG: kernel NULL pointer dereference, address: 00000000
CPU: 1 PID: 40 Comm: kworker/u5:0 Not tainted 6.2.0-rc5 #4
Workqueue: erofs_worker z_erofs_decompressqueue_work
EIP: z_erofs_lzma_decompress+0x34b/0x8ac
z_erofs_decompress+0x12/0x14
z_erofs_decompress_queue+0x7e7/0xb1c
z_erofs_decompressqueue_work+0x32/0x60
process_one_work+0x24b/0x4d8
? process_one_work+0x1a4/0x4d8
worker_thread+0x14c/0x3fc
kthread+0xe6/0x10c
? rescuer_thread+0x358/0x358
? kthread_complete_and_exit+0x18/0x18
ret_from_fork+0x1c/0x28
---[ end trace 0000000000000000 ]---
The bug is trivial and should be fixed now. It has no impact on
!HIGHMEM platforms.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.16 | 6.1.20 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 6.1.20-1 | — |
| Debian 13 | linux | 6.1.20-1 | — |
| Debian 12 | linux | 6.1.20-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-realtime +1 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Advisories 1
- WID-SEC-2025-0932 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 22, 2026