CVE-2025-68198
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: crash: fix crashkernel resource shrink When crashkernel is configured with a high reservation, shrinking its value below the low crashkernel reservation causes two issues: 1. Invalid crashkernel resource objects 2. Kernel crash if crashkernel shrinking is done twice For example, with crashkernel=200M,high, the kernel reserves 200MB of high memory and some default low memory (say 256MB). The reservation appears as: cat /proc/iomem | grep -i crash af000000-beffffff : Crash kernel 433000000-43f7fffff : Crash kernel If crashkernel is then shrunk to 50MB (echo 52428800 > /sys/kernel/kexec_crash_size), /proc/iomem still shows 256MB reserved: af000000-beffffff : Crash kernel Instead, it should show 50MB: af000000-b21fffff : Crash kernel Further shrinking crashkernel to 40MB causes a kernel crash with the following trace (x86): BUG: kernel NULL pointer dereference, address: 0000000000000038 PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI <snip...> Call Trace: <TASK> ? __die_body.cold+0x19/0x27 ? page_fault_oops+0x15a/0x2f0 ? search_module_extables+0x19/0x60 ? search_bpf_extables+0x5f/0x80 ? exc_page_fault+0x7e/0x180 ? asm_exc_page_fault+0x26/0x30 ? __release_resource+0xd/0xb0 release_resource+0x26/0x40 __crash_shrink_memory+0xe5/0x110 crash_shrink_memory+0x12a/0x190 kexec_crash_size_store+0x41/0x80 kernfs_fop_write_iter+0x141/0x1f0 vfs_write+0x294/0x460 ksys_write+0x6d/0xf0 <snip...> This happens because __crash_shrink_memory()/kernel/crash_core.c incorrectly updates the crashk_res resource object even when crashk_low_res should be updated. Fix this by ensuring the correct crashkernel resource object is updated when shrinking crashkernel memory.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
An adversary that can cause a resource counter to become inaccurate may be able to create situations where resources are not accounted for and not released, thus causing resources to become scarce for future needs.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An adversary that can cause a resource counter to become inaccurate may be able to force an error that causes the product to crash or exit out of its current operation.
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