In the Linux kernel, the following vulnerability has been resolved:
powerpc/rtas_flash: allow user copy to flash block cache objects
With hardened usercopy enabled (CONFIG_HARDENED_USERCOPY=y), using the /proc/powerpc/rtas/firmware_update interface to prepare a system firmware update yields a BUG():
kernel BUG at mm/usercopy.c:102! Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 0 PID: 2232 Comm: dd Not tainted 6.5.0-rc3+ #2 Hardware name: IBM,8408-E8E POWER8E (raw) 0x4b0201 0xf000004 of:IBM,FW860.50 (SV860_146) hv:phyp pSeries NIP: c0000000005991d0 LR: c0000000005991cc CTR: 0000000000000000 REGS: c0000000148c76a0 TRAP: 0700 Not tainted (6.5.0-rc3+) MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 24002242 XER: 0000000c CFAR: c0000000001fbd34 IRQMASK: 0 [ ... GPRs omitted ... ] NIP usercopy_abort+0xa0/0xb0 LR usercopy_abort+0x9c/0xb0 Call Trace: usercopy_abort+0x9c/0xb0 (unreliable) __check_heap_object+0x1b4/0x1d0 __check_object_size+0x2d0/0x380 rtas_flash_write+0xe4/0x250 proc_reg_write+0xfc/0x160 vfs_write+0xfc/0x4e0 ksys_write+0x90/0x160 system_call_exception+0x178/0x320 system_call_common+0x160/0x2c4
The blocks of the firmware image are copied directly from user memory to objects allocated from flash_block_cache, so flash_block_cache must be created using kmem_cache_create_usercopy() to mark it safe for user access.
[mpe: Trim and indent oops]
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernel-tools-debuginfoUpgrade bpftoolUpgrade kernel-livepatch-5.15.128-80.144Upgrade kernel-headersUpgrade kernel-debuginfoUpgrade kernelUpgrade python-perf-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-livepatch-5.10.192-182.736Upgrade kernel-develUpgrade python-perfUpgrade bpftool-debuginfoUpgrade kernel-tools-develUpgrade perf-debuginfoUpgrade kernel-toolsUpgrade kernel-debuginfo-common-aarch64Upgrade perf | May 20, 2026 | May 20, 2026 |
| Amazon_linux_2023 | — | Upgrade kernel-toolsUpgrade kernel-libbpf-staticUpgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-headersUpgrade kernel-debuginfoUpgrade python3-perfUpgrade bpftoolUpgrade kernelUpgrade python3-perf-debuginfoUpgrade kernel-tools-debuginfoUpgrade perfUpgrade kernel-develUpgrade perf-debuginfoUpgrade kernel-libbpf-develUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-libbpfUpgrade kernel-livepatch-6.1.49-69.116Upgrade kernel-tools-devel | Oct 16, 2025 | Oct 1, 2025 |
| Debian | — | Upgrade linux | Oct 3, 2025 | Oct 3, 2025 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Oct 1, 2025 |
| Ubuntu | — | Upgrade linux-gcp-5.4Upgrade linux-nvidia-tegra-5.15Upgrade linux-ibm-5.4Upgrade linux-gkeopUpgrade linux-gcp-fipsUpgrade linux-gcpUpgrade linux-ibm-5.15Upgrade linux-intel-iotgUpgrade linux-intel-iot-realtimeUpgrade linux-nvidia-tegra-igxUpgrade linux-gkeUpgrade linuxUpgrade linux-fipsUpgrade linux-oracle-5.4Upgrade linux-oracle-5.15Upgrade linux-riscv-5.15Upgrade linux-nvidia-tegraUpgrade linux-azure-fipsUpgrade linux-iotUpgrade linux-aws-5.4Upgrade linux-gcp-5.15Upgrade linux-lowlatency-hwe-5.15Upgrade linux-oracleUpgrade linux-realtimeUpgrade linux-raspi-5.4Upgrade linux-azureUpgrade linux-hwe-5.4Upgrade linux-lowlatencyUpgrade linux-nvidiaUpgrade linux-hwe-5.15Upgrade linux-intel-iotg-5.15Upgrade linux-xilinx-zynqmpUpgrade linux-bluefieldUpgrade linux-awsUpgrade linux-aws-5.15Upgrade linux-ibmUpgrade linux-raspiUpgrade linux-kvmUpgrade linux-aws-fipsUpgrade linux-azure-5.15Upgrade linux-azure-5.4 | Oct 10, 2025 | Oct 1, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Oct 15, 2025 | Oct 1, 2025 |
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