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CVE-2025-68198

Estado: AplazadaSin puntuar—

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

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Instead, it should show 50MB: af000000-b21fffff : Crash kernel

Further shrinking crashkernel to 40MB causes a kernel crash with the following trace (x86):

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.

Detalles técnicos trazas, registros y código del informe original
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...>

CVSS

NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2025-68198",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "16c6006af4d4e70ecef93977a5314409d931020b",
              "lessThan": "f01f9c348d76d40bf104a94449e3ce4057fdefee",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "16c6006af4d4e70ecef93977a5314409d931020b",
              "lessThan": "f89c5e7077f63e45e8ba5a77b7cf0803130367e6",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "16c6006af4d4e70ecef93977a5314409d931020b",
              "lessThan": "a2bd247f8c6c5ac3f0ba823a2fffd77bb9cdf618",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "16c6006af4d4e70ecef93977a5314409d931020b",
              "lessThan": "00fbff75c5acb4755f06f08bd1071879c63940c5",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "kernel/crash_core.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.5"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.5",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.118",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.59",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.17.9",
              "versionType": "semver",
              "lessThanOrEqual": "6.17.*"
            },
            {
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "kernel/crash_core.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-12-16T14:15:52.590",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/00fbff75c5acb4755f06f08bd1071879c63940c5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a2bd247f8c6c5ac3f0ba823a2fffd77bb9cdf618",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f01f9c348d76d40bf104a94449e3ce4057fdefee",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f89c5e7077f63e45e8ba5a77b7cf0803130367e6",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrash: fix crashkernel resource shrink\n\nWhen crashkernel is configured with a high reservation, shrinking its\nvalue below the low crashkernel reservation causes two issues:\n\n1. Invalid crashkernel resource objects\n2. Kernel crash if crashkernel shrinking is done twice\n\nFor example, with crashkernel=200M,high, the kernel reserves 200MB of high\nmemory and some default low memory (say 256MB).  The reservation appears\nas:\n\ncat /proc/iomem | grep -i crash\naf000000-beffffff : Crash kernel\n433000000-43f7fffff : Crash kernel\n\nIf crashkernel is then shrunk to 50MB (echo 52428800 >\n/sys/kernel/kexec_crash_size), /proc/iomem still shows 256MB reserved:\naf000000-beffffff : Crash kernel\n\nInstead, it should show 50MB:\naf000000-b21fffff : Crash kernel\n\nFurther shrinking crashkernel to 40MB causes a kernel crash with the\nfollowing trace (x86):\n\nBUG: kernel NULL pointer dereference, address: 0000000000000038\nPGD 0 P4D 0\nOops: 0000 [#1] PREEMPT SMP NOPTI\n<snip...>\nCall Trace: <TASK>\n? __die_body.cold+0x19/0x27\n? page_fault_oops+0x15a/0x2f0\n? search_module_extables+0x19/0x60\n? search_bpf_extables+0x5f/0x80\n? exc_page_fault+0x7e/0x180\n? asm_exc_page_fault+0x26/0x30\n? __release_resource+0xd/0xb0\nrelease_resource+0x26/0x40\n__crash_shrink_memory+0xe5/0x110\ncrash_shrink_memory+0x12a/0x190\nkexec_crash_size_store+0x41/0x80\nkernfs_fop_write_iter+0x141/0x1f0\nvfs_write+0x294/0x460\nksys_write+0x6d/0xf0\n<snip...>\n\nThis happens because __crash_shrink_memory()/kernel/crash_core.c\nincorrectly updates the crashk_res resource object even when\ncrashk_low_res should be updated.\n\nFix this by ensuring the correct crashkernel resource object is updated\nwhen shrinking crashkernel memory."
    }
  ],
  "lastModified": "2026-06-17T09:58:43.357",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}