CVE-2026-64417 (GCVE-0-2026-64417)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-08-17 04:55
VLAI
Title
mm: shrinker: fix NULL pointer dereference in debugfs
Summary
In the Linux kernel, the following vulnerability has been resolved: mm: shrinker: fix NULL pointer dereference in debugfs shrinker_debugfs_add() creates both "count" and "scan" debugfs files unconditionally. That assumes every shrinker implements both count_objects() and scan_objects(), which is not guaranteed. For example, the xen-backend shrinker sets count_objects() but leaves scan_objects() NULL, so writing to its scan file calls through a NULL function pointer and panics the kernel: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. Call Trace: <TASK> shrinker_debugfs_scan_write+0x12e/0x270 full_proxy_write+0x5f/0x90 vfs_write+0xde/0x420 ? filp_flush+0x75/0x90 ? filp_close+0x1d/0x30 ? do_dup2+0xb8/0x120 ksys_write+0x68/0xf0 ? filp_flush+0x75/0x90 do_syscall_64+0xb3/0x5b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e The count path has the same issue in principle if a shrinker omits count_objects(). To fix it, only create "count" and "scan" debugfs files when the corresponding callbacks are present.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bbf535fd6f06b94b9d07ed6f09397a936d4a58d8 , < ebb45c2648b1f60715fd283700f651e05e431231 (git)
Affected: bbf535fd6f06b94b9d07ed6f09397a936d4a58d8 , < 09d2407985b8ce3e831f9d4310fe7ac06a6b3ae9 (git)
Affected: bbf535fd6f06b94b9d07ed6f09397a936d4a58d8 , < 36f8534f461222291a74156ab91f3ba9f09b6f93 (git)
Affected: bbf535fd6f06b94b9d07ed6f09397a936d4a58d8 , < 006467ab932698612398f853344a7405164541f4 (git)
Affected: bbf535fd6f06b94b9d07ed6f09397a936d4a58d8 , < b9beed2322f3538b0d2d53307062da4102b8d8d8 (git)
Affected: bbf535fd6f06b94b9d07ed6f09397a936d4a58d8 , < e30453c61e185e914fde83c650e268067b140218 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.0
Unaffected: 0 , < 6.0 (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.96 , ≤ 6.12.* (semver)
Unaffected: 6.18.39 , ≤ 6.18.* (semver)
Unaffected: 7.1.4 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/shrinker_debug.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ebb45c2648b1f60715fd283700f651e05e431231",
              "status": "affected",
              "version": "bbf535fd6f06b94b9d07ed6f09397a936d4a58d8",
              "versionType": "git"
            },
            {
              "lessThan": "09d2407985b8ce3e831f9d4310fe7ac06a6b3ae9",
              "status": "affected",
              "version": "bbf535fd6f06b94b9d07ed6f09397a936d4a58d8",
              "versionType": "git"
            },
            {
              "lessThan": "36f8534f461222291a74156ab91f3ba9f09b6f93",
              "status": "affected",
              "version": "bbf535fd6f06b94b9d07ed6f09397a936d4a58d8",
              "versionType": "git"
            },
            {
              "lessThan": "006467ab932698612398f853344a7405164541f4",
              "status": "affected",
              "version": "bbf535fd6f06b94b9d07ed6f09397a936d4a58d8",
              "versionType": "git"
            },
            {
              "lessThan": "b9beed2322f3538b0d2d53307062da4102b8d8d8",
              "status": "affected",
              "version": "bbf535fd6f06b94b9d07ed6f09397a936d4a58d8",
              "versionType": "git"
            },
            {
              "lessThan": "e30453c61e185e914fde83c650e268067b140218",
              "status": "affected",
              "version": "bbf535fd6f06b94b9d07ed6f09397a936d4a58d8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/shrinker_debug.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.96",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: shrinker: fix NULL pointer dereference in debugfs\n\nshrinker_debugfs_add() creates both \"count\" and \"scan\" debugfs files\nunconditionally.\n\nThat assumes every shrinker implements both count_objects() and\nscan_objects(), which is not guaranteed.  For example, the xen-backend\nshrinker sets count_objects() but leaves scan_objects() NULL, so writing\nto its scan file calls through a NULL function pointer and panics the\nkernel:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nRIP: 0010:0x0\nCode: Unable to access opcode bytes at 0xffffffffffffffd6.\nCall Trace:\n \u003cTASK\u003e\n shrinker_debugfs_scan_write+0x12e/0x270\n full_proxy_write+0x5f/0x90\n vfs_write+0xde/0x420\n ? filp_flush+0x75/0x90\n ? filp_close+0x1d/0x30\n ? do_dup2+0xb8/0x120\n ksys_write+0x68/0xf0\n ? filp_flush+0x75/0x90\n do_syscall_64+0xb3/0x5b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nThe count path has the same issue in principle if a shrinker omits\ncount_objects().\n\nTo fix it, only create \"count\" and \"scan\" debugfs files when the\ncorresponding callbacks are present."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:55:16.708Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ebb45c2648b1f60715fd283700f651e05e431231"
        },
        {
          "url": "https://git.kernel.org/stable/c/09d2407985b8ce3e831f9d4310fe7ac06a6b3ae9"
        },
        {
          "url": "https://git.kernel.org/stable/c/36f8534f461222291a74156ab91f3ba9f09b6f93"
        },
        {
          "url": "https://git.kernel.org/stable/c/006467ab932698612398f853344a7405164541f4"
        },
        {
          "url": "https://git.kernel.org/stable/c/b9beed2322f3538b0d2d53307062da4102b8d8d8"
        },
        {
          "url": "https://git.kernel.org/stable/c/e30453c61e185e914fde83c650e268067b140218"
        }
      ],
      "title": "mm: shrinker: fix NULL pointer dereference in debugfs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64417",
    "datePublished": "2026-07-25T08:50:56.800Z",
    "dateReserved": "2026-07-19T15:36:31.786Z",
    "dateUpdated": "2026-08-17T04:55:16.708Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-64417",
      "date": "2026-08-16",
      "epss": "0.00173",
      "percentile": "0.06978"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-64417\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-07-25T10:17:25.567\",\"lastModified\":\"2026-08-17T05:17:45.513\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmm: shrinker: fix NULL pointer dereference in debugfs\\n\\nshrinker_debugfs_add() creates both \\\"count\\\" and \\\"scan\\\" debugfs files\\nunconditionally.\\n\\nThat assumes every shrinker implements both count_objects() and\\nscan_objects(), which is not guaranteed.  For example, the xen-backend\\nshrinker sets count_objects() but leaves scan_objects() NULL, so writing\\nto its scan file calls through a NULL function pointer and panics the\\nkernel:\\n\\nBUG: kernel NULL pointer dereference, address: 0000000000000000\\nRIP: 0010:0x0\\nCode: Unable to access opcode bytes at 0xffffffffffffffd6.\\nCall Trace:\\n \u003cTASK\u003e\\n shrinker_debugfs_scan_write+0x12e/0x270\\n full_proxy_write+0x5f/0x90\\n vfs_write+0xde/0x420\\n ? filp_flush+0x75/0x90\\n ? filp_close+0x1d/0x30\\n ? do_dup2+0xb8/0x120\\n ksys_write+0x68/0xf0\\n ? filp_flush+0x75/0x90\\n do_syscall_64+0xb3/0x5b0\\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\\n\\nThe count path has the same issue in principle if a shrinker omits\\ncount_objects().\\n\\nTo fix it, only create \\\"count\\\" and \\\"scan\\\" debugfs files when the\\ncorresponding callbacks are present.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"mm/shrinker_debug.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"bbf535fd6f06b94b9d07ed6f09397a936d4a58d8\",\"lessThan\":\"ebb45c2648b1f60715fd283700f651e05e431231\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bbf535fd6f06b94b9d07ed6f09397a936d4a58d8\",\"lessThan\":\"09d2407985b8ce3e831f9d4310fe7ac06a6b3ae9\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bbf535fd6f06b94b9d07ed6f09397a936d4a58d8\",\"lessThan\":\"36f8534f461222291a74156ab91f3ba9f09b6f93\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bbf535fd6f06b94b9d07ed6f09397a936d4a58d8\",\"lessThan\":\"006467ab932698612398f853344a7405164541f4\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bbf535fd6f06b94b9d07ed6f09397a936d4a58d8\",\"lessThan\":\"b9beed2322f3538b0d2d53307062da4102b8d8d8\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bbf535fd6f06b94b9d07ed6f09397a936d4a58d8\",\"lessThan\":\"e30453c61e185e914fde83c650e268067b140218\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"mm/shrinker_debug.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.0\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.178\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.145\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.96\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.39\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.4\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/006467ab932698612398f853344a7405164541f4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/09d2407985b8ce3e831f9d4310fe7ac06a6b3ae9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/36f8534f461222291a74156ab91f3ba9f09b6f93\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b9beed2322f3538b0d2d53307062da4102b8d8d8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e30453c61e185e914fde83c650e268067b140218\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ebb45c2648b1f60715fd283700f651e05e431231\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-07-30T04:05:10+00:00",
      "cve": "CVE-2026-64417",
      "id": "CVE-2026-64417",
      "initial_release_date": "2026-07-25T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: mm: shrinker: fix NULL pointer dereference in debugfs",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64417.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-05T00:31:52Z",
      "cve": "CVE-2026-64417",
      "id": "CVE-2026-64417",
      "initial_release_date": "2026-07-25T15:59:44Z",
      "product_status:known_affected": "131",
      "product_status:known_not_affected": "167",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64417",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64417.json",
      "version": "4"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.