Description
In the Linux kernel, the following vulnerability has been resolved:
block, bfq: fix uaf for accessing waker_bfqq after splitting
After commit 42c306ed7233 ("block, bfq: don't break merge chain in
bfq_split_bfqq()"), if the current procress is the last holder of bfqq,
the bfqq can be freed after bfq_split_bfqq(). Hence recored the bfqq and
then access bfqq->waker_bfqq may trigger UAF. What's more, the waker_bfqq
may in the merge chain of bfqq, hence just recored waker_bfqq is still
not safe.
Fix the problem by adding a helper bfq_waker_bfqq() to check if
bfqq->waker_bfqq is in the merge chain, and current procress is the only
holder.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 4.19.323 – < 4.20, 5.4.285 – < 5.5, 5.10.227 – < 5.11 | 4.20 |
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.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-raspi-realtime | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +26 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +13 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux +10 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | linux-aws-5.4 +6 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP6 | kernel-64kb +6 | 6.4.0-150600.23.33.1 | SUSE-SU-2025:0154-1 |
| SLES 15 SP6 | kernel-azure +2 | 6.4.0-150600.8.23.1 | SUSE-SU-2025:0117-1 |
| SLES 15 SP6 | kernel-coco +3 | 6.4.0-15061.12.coco15sp6.1 | SUSE-SU-2025:0289-1 |
| SLES 15 SP6 | kernel-default-base | 6.4.0-150600.23.33.1.150600.12.14.1 | SUSE-SU-2025:0154-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 6.1 | kernel-default-base | 6.4.0-24.1.21.4 | SUSE-SU-2025:20248-1 |
| SLE Micro 6.1 | kernel-livepatch-MICRO-6-0-RT_Update_5 | 1-1.1 | SUSE-SU-2025:20249-1 |
| SLE Micro 6.1 | kernel-livepatch-MICRO-6-0_Update_5 | 1-1.2 | SUSE-SU-2025:20248-1 |
| SLE Micro 6.1 | kernel-rt +4 | 6.4.0-25.1 | SUSE-SU-2025:20249-1, SUSE-SU-2025:20248-1 |
| SLE Micro 6.0 | kernel-default-base | 6.4.0-24.1.21.4 | SUSE-SU-2025:20165-1 |
| SLE Micro 6.0 | kernel-livepatch-MICRO-6-0-RT_Update_5 | 1-1.1 | SUSE-SU-2025:20166-1 |
| SLE Micro 6.0 | kernel-livepatch-MICRO-6-0_Update_5 | 1-1.2 | SUSE-SU-2025:20165-1 |
| SLE Micro 6.0 | kernel-rt +4 | 6.4.0-25.1 | SUSE-SU-2025:20166-1, SUSE-SU-2025:20165-1 |
| SLE Live Patching 15 SP6 | kernel-default | 6.4.0-150600.23.33.1 | SUSE-SU-2025:0154-1 |
| SLE Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6-RT_Update_7 | 1-150600.1.3.1 | SUSE-SU-2025:0153-1 |
| SLE Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_7 | 1-150600.13.3.1 | SUSE-SU-2025:0154-1 |
| SUSE Real Time Module 15 SP6 | kernel-rt +3 | 6.4.0-150600.10.23.1 | SUSE-SU-2025:0153-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | kernel-source | 6.11.8-1.1 | openSUSE-SU-2024:14500-1 |
| openSUSE Tumbleweed | kernel-source-longterm | 6.12.11-1.1 | openSUSE-SU-2025:14705-1 |
| openSUSE Leap 15.6 | dtb-aarch64 +10 | 6.4.0-150600.23.33.1 | SUSE-SU-2025:0154-1 |
| openSUSE Leap 15.6 | kernel-azure +2 | 6.4.0-150600.8.23.1 | SUSE-SU-2025:0117-1 |
| openSUSE Leap 15.6 | kernel-default-base | 6.4.0-150600.23.33.1.150600.12.14.1 | SUSE-SU-2025:0154-1 |
| openSUSE Leap 15.6 | kernel-rt +3 | 6.4.0-150600.10.23.1 | SUSE-SU-2025:0153-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | kernel | 6.6.56.1-5 | — |
| Azure Linux 2 (CBL-Mariner) | kernel | 5.15.173.1-1 | — |
Advisories 11
- WID-SEC-2024-3251 Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Nov 11, 2026
- SUSE-SU-2025:20165-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:20166-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:20248-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:20249-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:0117-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:0153-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:0154-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2025:14705-1 kernel-devel-longterm-6.12.11-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:14500-1 kernel-devel-6.11.8-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:0289-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://git.kernel.org/stable/c/63a07379fdb6c72450cb05294461c6016b8b7726
- https://git.kernel.org/stable/c/de0456460f2abf921e356ed2bd8da87a376680bd
- https://git.kernel.org/stable/c/0780451f03bf518bc032a7c584de8f92e2d39d7f
- https://git.kernel.org/stable/c/0b8bda0ff17156cd3f60944527c9d8c9f99f1583
- https://git.kernel.org/stable/c/cae58d19121a70329cf971359e2518c93fec04fe
- https://git.kernel.org/stable/c/1ba0403ac6447f2d63914fb760c44a3b19c44eaf