CVE-2024-26768
NoneCVSS
—
EPSS
0.6%
Published
Apr 3, 2024
CISA due date
—
Cloudanix analysis
Some computers with certain processors may crash when starting up if they have too many processing cores, and updating the operating system fixes it.
- Exploitation
- Local Privilege
- Attacker needs
- None
- Complexity
- Theoretical
- Impact
- Denial Of Service
- Component
- OS kernel
- Class
- Buffer Overflow
- Remediation
- Upgrade
- Effort
- Medium
- Patch risk
- Low
What it actually does
Array acpi_core_pic sized to NR_CPUS (default 64) instead of MAX_CORE_PIC overflows during MADT parsing on LoongArch platforms with more physical cores than logical CPUs, causing kernel paging fault and early boot crash.
Why it matters to the business
LoongArch servers or virtual machines configured with more than 64 CPUs fail to boot, resulting in complete loss of system availability until the kernel is updated or CPU count is reduced.
How an attack unfolds
No remote or privilege-escalation exploitation is known; the flaw is triggered automatically at boot when the firmware MADT table enumerates more physical cores than NR_CPUS, causing an out-of-bounds write during platform initialization before user-space starts.
How to fix it
Upgrade the Linux kernel to the commit 88e189bd16e5889e44a41b3309558ebab78b9280 or later stable releases that resize acpi_core_pic to MAX_CORE_PIC; rebuild and deploy the fixed kernel image.
How to confirm the fix worked
Confirm the running kernel contains commit 88e189bd16e5889e44a41b3309558ebab78b9280, then boot with qemu -smp 128 on LoongArch and verify successful initialization without the paging-request oops.
Typical attack path
- Boot kernel on LoongArch hardware or QEMU with -smp >64
- Firmware supplies MADT with >NR_CPUS physical core entries
- acpi_core_pic array overflows during early MADT walk
- Kernel dereferences invalid address and panics
How to detect it
Review early kernel logs (dmesg or serial console) for the exact oops string containing 'Unable to handle kernel paging request at virtual address 0000420000004259' and 'efi_runtime_init' during platform_init on LoongArch systems.
- Unable to handle kernel paging request at virtual address 0000420000004259
- era == 90000000037a5f0c
- efi_runtime_init+0x30/0x94
- platform_init+0x214/0x250
What your security team should do
- Prioritize kernel update on all LoongArch production systems within the next maintenance window
- Add boot-time CPU count checks to monitoring to detect potential crash conditions before rollout
- Track downstream package maintainers for backported fixes in distribution kernels
The record
In the Linux kernel, the following vulnerability has been resolved: LoongArch: Change acpi_core_pic[NR_CPUS] to acpi_core_pic[MAX_CORE_PIC] With default config, the value of NR_CPUS is 64. When HW platform has more then 64 cpus, system will crash on these platforms. MAX_CORE_PIC is the maximum cpu number in MADT table (max physical number) which can exceed the supported maximum cpu number (NR_CPUS, max logical number), but kernel should not crash. Kernel should boot cpus with NR_CPUS, let the remainder cpus stay in BIOS. The potential crash reason is that the array acpi_core_pic[NR_CPUS] can be overflowed when parsing MADT table, and it is obvious that CORE_PIC should be corresponding to physical core rather than logical core, so it is better to define the array as acpi_core_pic[MAX_CORE_PIC]. With the patch, system can boot up 64 vcpus with qemu parameter -smp 128, otherwise system will crash with the following message. [ 0.000000] CPU 0 Unable to handle kernel paging request at virtual address 0000420000004259, era == 90000000037a5f0c, ra == 90000000037a46ec [ 0.000000] Oops[#1]: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.8.0-rc2+ #192 [ 0.000000] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022 [ 0.000000] pc 90000000037a5f0c ra 90000000037a46ec tp 9000000003c90000 sp 9000000003c93d60 [ 0.000000] a0 0000000000000019 a1 9000000003d93bc0 a2 0000000000000000 a3 9000000003c93bd8 [ 0.000000] a4 9000000003c93a74 a5 9000000083c93a67 a6 9000000003c938f0 a7 0000000000000005 [ 0.000000] t0 0000420000004201 t1 0000000000000000 t2 0000000000000001 t3 0000000000000001 [ 0.000000] t4 0000000000000003 t5 0000000000000000 t6 0000000000000030 t7 0000000000000063 [ 0.000000] t8 0000000000000014 u0 ffffffffffffffff s9 0000000000000000 s0 9000000003caee98 [ 0.000000] s1 90000000041b0480 s2 9000000003c93da0 s3 9000000003c93d98 s4 9000000003c93d90 [ 0.000000] s5 9000000003caa000 s6 000000000a7fd000 s7 000000000f556b60 s8 000000000e0a4330 [ 0.000000] ra: 90000000037a46ec platform_init+0x214/0x250 [ 0.000000] ERA: 90000000037a5f0c efi_runtime_init+0x30/0x94 [ 0.000000] CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE) [ 0.000000] PRMD: 00000000 (PPLV0 -PIE -PWE) [ 0.000000] EUEN: 00000000 (-FPE -SXE -ASXE -BTE) [ 0.000000] ECFG: 00070800 (LIE=11 VS=7) [ 0.000000] ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0) [ 0.000000] BADV: 0000420000004259 [ 0.000000] PRID: 0014c010 (Loongson-64bit, Loongson-3A5000) [ 0.000000] Modules linked in: [ 0.000000] Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____)) [ 0.000000] Stack : 9000000003c93a14 9000000003800898 90000000041844f8 90000000037a46ec [ 0.000000] 000000000a7fd000 0000000008290000 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 0000000000000000 00000000019d8000 000000000f556b60 [ 0.000000] 000000000a7fd000 000000000f556b08 9000000003ca7700 9000000003800000 [ 0.000000] 9000000003c93e50 9000000003800898 9000000003800108 90000000037a484c [ 0.000000] 000000000e0a4330 000000000f556b60 000000000a7fd000 000000000f556b08 [ 0.000000] 9000000003ca7700 9000000004184000 0000000000200000 000000000e02b018 [ 0.000000] 000000000a7fd000 90000000037a0790 9000000003800108 0000000000000000 [ 0.000000] 0000000000000000 000000000e0a4330 000000000f556b60 000000000a7fd000 [ 0.000000] 000000000f556b08 000000000eaae298 000000000eaa5040 0000000000200000 [ 0.000000] ... [ 0.000000] Call Trace: [ 0.000000] [<90000000037a5f0c>] efi_runtime_init+0x30/0x94 [ 0.000000] [<90000000037a46ec>] platform_init+0x214/0x250 [ 0.000000] [<90000000037a484c>] setup_arch+0x124/0x45c [ 0.000000] [<90000000037a0790>] start_kernel+0x90/0x670 [ 0.000000] [<900000000378b0d8>] kernel_entry+0xd8/0xdc
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Debian:11 | linux | 0 | No fix |
| Debian:12 | linux | 0 | No fix |
| Debian:13 | linux | 0 | 6.7.7-1 |
| Linux | Kernel | 5.19.0 | 6.6.19 |
| Ubuntu:16.04:LTS | linux-hwe-edge | 0 | No fix |
| Ubuntu:18.04:LTS | linux-aws-5.0 | 0 | No fix |
| Ubuntu:18.04:LTS | linux-aws-5.3 | 0 | No fix |
| Ubuntu:18.04:LTS | linux-azure | 0 | No fix |
| Ubuntu:18.04:LTS | linux-azure-5.3 | 0 | No fix |
| Ubuntu:18.04:LTS | linux-azure-edge | 0 | No fix |
| Ubuntu:18.04:LTS | linux-gcp | 0 | No fix |
| Ubuntu:18.04:LTS | linux-gcp-5.3 | 0 | No fix |
| Ubuntu:18.04:LTS | linux-gke-4.15 | 0 | No fix |
| Ubuntu:18.04:LTS | linux-gke-5.4 | 0 | No fix |
| Ubuntu:18.04:LTS | linux-gkeop-5.4 | 0 | No fix |
| Ubuntu:18.04:LTS | linux-hwe | 0 | No fix |
| Ubuntu:18.04:LTS | linux-hwe-edge | 0 | No fix |
| Ubuntu:18.04:LTS | linux-oem | 0 | No fix |
| Ubuntu:18.04:LTS | linux-oracle-5.0 | 0 | No fix |
| Ubuntu:18.04:LTS | linux-oracle-5.3 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-aws-5.11 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-aws-5.13 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-aws-5.8 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-azure-5.11 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-azure-5.13 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-azure-5.8 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-azure-fde | 0 | No fix |
| Ubuntu:20.04:LTS | linux-gcp-5.11 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-gcp-5.13 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-gcp-5.8 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-gke | 0 | No fix |
| Ubuntu:20.04:LTS | linux-gke-5.15 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-hwe-5.11 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-hwe-5.13 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-hwe-5.8 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-intel-5.13 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-oem-5.10 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-oem-5.13 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-oem-5.14 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-oem-5.6 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-oracle-5.11 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-oracle-5.13 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-oracle-5.8 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-raspi2 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-riscv | 0 | No fix |
| Ubuntu:20.04:LTS | linux-riscv-5.11 | 0 | No fix |
| Ubuntu:20.04:LTS | linux-riscv-5.8 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-allwinner-5.19 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-aws-5.19 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-aws-6.2 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-aws-6.8 | 0 | 6.8.0-1009.9~22.04.2 |
| Ubuntu:22.04:LTS | linux-azure-5.19 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-azure-6.2 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-azure-6.8 | 0 | 6.8.0-1008.8~22.04.1 |
| Ubuntu:22.04:LTS | linux-azure-fde-5.19 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-azure-fde-6.2 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-gcp-5.19 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-gcp-6.2 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-gcp-6.8 | 0 | 6.8.0-1010.11~22.04.1 |
| Ubuntu:22.04:LTS | linux-hwe-5.19 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-hwe-6.2 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-hwe-6.8 | 0 | 6.8.0-38.38~22.04.1 |
| Ubuntu:22.04:LTS | linux-intel-iot-realtime | 0 | No fix |
| Ubuntu:22.04:LTS | linux-lowlatency-hwe-5.19 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-lowlatency-hwe-6.2 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-lowlatency-hwe-6.8 | 0 | 6.8.0-38.38.1~22.04.2 |
| Ubuntu:22.04:LTS | linux-nvidia-6.2 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-nvidia-6.8 | 0 | 6.8.0-1008.8~22.04.1 |
| Ubuntu:22.04:LTS | linux-nvidia-tegra | 0 | No fix |
| Ubuntu:22.04:LTS | linux-nvidia-tegra-igx | 0 | No fix |
| Ubuntu:22.04:LTS | linux-oem-5.17 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-oem-6.0 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-oem-6.1 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-oracle-6.8 | 0 | 6.8.0-1006.6~22.04.3 |
| Ubuntu:22.04:LTS | linux-realtime | 0 | No fix |
| Ubuntu:22.04:LTS | linux-riscv | 0 | No fix |
| Ubuntu:22.04:LTS | linux-riscv-5.19 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-riscv-6.8 | 0 | 6.8.0-38.38.1~22.04.1 |
| Ubuntu:22.04:LTS | linux-starfive-5.19 | 0 | No fix |
| Ubuntu:22.04:LTS | linux-starfive-6.2 | 0 | No fix |
| Ubuntu:22.04:LTS:for:NVIDIA:BlueField | linux-bluefield | 0 | No fix |
| Ubuntu:24.04:LTS | linux-gkeop | 0 | 6.8.0-1001.3 |
| Ubuntu:24.04:LTS | linux-nvidia | 0 | 6.8.0-1007.7 |
| Ubuntu:24.04:LTS | linux-nvidia-lowlatency | 0 | 6.8.0-1009.9.1 |
| Ubuntu:24.04:LTS | linux-oem-6.11 | 0 | 6.11.0-1007.7 |
| Ubuntu:24.04:LTS | linux-oem-6.8 | 0 | 6.8.0-1003.3 |
| Ubuntu:24.04:LTS | linux-raspi-realtime | 0 | No fix |
| Ubuntu:24.04:LTS | linux-realtime | 0 | 6.8.0-1008.19 |
| Ubuntu:24.10 | linux-realtime | 0 | 6.11.0-1001.1 |
| Ubuntu:25.10 | linux-azure-fde | 0 | No fix |
| Ubuntu:Pro:16.04:LTS | linux-hwe-edge | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-aws-5.0 | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-aws-5.3 | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-azure | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-azure-5.3 | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-azure-edge | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-gcp | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-gcp-5.3 | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-gke-4.15 | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-gke-5.4 | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-gkeop-5.4 | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-hwe | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-hwe-edge | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-oem | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-oracle-5.0 | 0 | No fix |
| Ubuntu:Pro:18.04:LTS | linux-oracle-5.3 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-aws-5.11 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-aws-5.13 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-aws-5.8 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-azure-5.11 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-azure-5.13 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-azure-5.8 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-azure-fde | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-gcp-5.11 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-gcp-5.13 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-gcp-5.8 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-gke | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-gke-5.15 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-hwe-5.11 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-hwe-5.13 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-hwe-5.8 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-intel-5.13 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-nvidia-tegra-5.15 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-oem-5.10 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-oem-5.13 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-oem-5.14 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-oem-5.6 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-oracle-5.11 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-oracle-5.13 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-oracle-5.8 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-raspi2 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-riscv | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-riscv-5.11 | 0 | No fix |
| Ubuntu:Pro:20.04:LTS | linux-riscv-5.8 | 0 | No fix |
| Ubuntu:Pro:22.04:LTS:Realtime:Kernel | linux-intel-iot-realtime | 0 | No fix |
| Ubuntu:Pro:22.04:LTS:Realtime:Kernel | linux-realtime | 0 | No fix |
| Ubuntu:Pro:24.04:LTS:Realtime:Kernel | linux-raspi-realtime | 0 | 6.8.0-2001.1 |
| Ubuntu:Pro:FIPS-preview:22.04:LTS | linux-aws-fips | 0 | No fix |
| Ubuntu:Pro:FIPS-preview:22.04:LTS | linux-azure-fips | 0 | No fix |
| Ubuntu:Pro:FIPS-preview:22.04:LTS | linux-fips | 0 | No fix |
| Ubuntu:Pro:FIPS-preview:22.04:LTS | linux-gcp-fips | 0 | No fix |
| Ubuntu:Pro:FIPS-updates:22.04:LTS | linux-aws-fips | 0 | No fix |
| Ubuntu:Pro:FIPS-updates:22.04:LTS | linux-azure-fips | 0 | No fix |
| Ubuntu:Pro:FIPS-updates:22.04:LTS | linux-fips | 0 | No fix |
| Ubuntu:Pro:FIPS-updates:22.04:LTS | linux-gcp-fips | 0 | No fix |
| Ubuntu:Pro:Realtime:24.04:LTS | linux-raspi-realtime | 0 | 6.8.0-2001.1 |
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