Vulnerability-Lookup

CVE-2026-64368 (GCVE-0-2026-64368)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-07-27 04:59

Title

mm/slab: do not limit zeroing to orig_size when only red zoning is enabled

Summary

In the Linux kernel, the following vulnerability has been resolved: mm/slab: do not limit zeroing to orig_size when only red zoning is enabled When init (zeroing) on allocation is requested, for kmalloc() we generally have to zero the full object size even if a smaller size is requested, in order to provide krealloc()'s __GFP_ZERO guarantees. But if we track the requested size, krealloc() uses that information to do the right thing, so we can zero only the requested size. With red zoning also enabled, any extra size became part of the red zone, so it must not be zeroed and thus we must zero only the requested size. However the current check is imprecise, and will trigger also when only SLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking the requested size). This means enabling red zoning alone can compromise krealloc()'s __GFP_ZERO contract. Fix this by using slub_debug_orig_size() instead, which is the exact check for whether the requested size is tracked. We don't need to care if red zoning is also enabled or not. Also update and expand the comment accordingly.

Severity

8.1 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/6256899c3a34674bb…
https://git.kernel.org/stable/c/7e706d50fa119eead…
https://git.kernel.org/stable/c/2382971aaaef5bf85…
https://git.kernel.org/stable/c/0d18ccef142f04433…
https://git.kernel.org/stable/c/648927ceb84021a25…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 , < 6256899c3a34674bba6076884aedbba49fc695e4 (git) Affected: 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 , < 7e706d50fa119eead6376bf0ef973e8d73a96030 (git) Affected: 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 , < 2382971aaaef5bf85a651234c64906f59580b8be (git) Affected: 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 , < 0d18ccef142f04433dfb2a0c120cf223d2b8a42c (git) Affected: 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 , < 648927ceb84021a25a0fbd5673740956f318d534 (git)
Linux	Linux	Affected: 6.2 Unaffected: 0 , < 6.2 (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-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/slub.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6256899c3a34674bba6076884aedbba49fc695e4",
              "status": "affected",
              "version": "9ce67395f5a0cdec6ce152d26bfda13b98b25c01",
              "versionType": "git"
            },
            {
              "lessThan": "7e706d50fa119eead6376bf0ef973e8d73a96030",
              "status": "affected",
              "version": "9ce67395f5a0cdec6ce152d26bfda13b98b25c01",
              "versionType": "git"
            },
            {
              "lessThan": "2382971aaaef5bf85a651234c64906f59580b8be",
              "status": "affected",
              "version": "9ce67395f5a0cdec6ce152d26bfda13b98b25c01",
              "versionType": "git"
            },
            {
              "lessThan": "0d18ccef142f04433dfb2a0c120cf223d2b8a42c",
              "status": "affected",
              "version": "9ce67395f5a0cdec6ce152d26bfda13b98b25c01",
              "versionType": "git"
            },
            {
              "lessThan": "648927ceb84021a25a0fbd5673740956f318d534",
              "status": "affected",
              "version": "9ce67395f5a0cdec6ce152d26bfda13b98b25c01",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/slub.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.2"
            },
            {
              "lessThan": "6.2",
              "status": "unaffected",
              "version": "0",
              "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-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.96",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc1",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slab: do not limit zeroing to orig_size when only red zoning is enabled\n\nWhen init (zeroing) on allocation is requested, for kmalloc() we\ngenerally have to zero the full object size even if a smaller size is\nrequested, in order to provide krealloc()\u0027s __GFP_ZERO guarantees.\n\nBut if we track the requested size, krealloc() uses that information to\ndo the right thing, so we can zero only the requested size. With red\nzoning also enabled, any extra size became part of the red zone, so it\nmust not be zeroed and thus we must zero only the requested size.\n\nHowever the current check is imprecise, and will trigger also when only\nSLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking\nthe requested size). This means enabling red zoning alone can compromise\nkrealloc()\u0027s __GFP_ZERO contract.\n\nFix this by using slub_debug_orig_size() instead, which is the exact\ncheck for whether the requested size is tracked. We don\u0027t need to care\nif red zoning is also enabled or not. Also update and expand the\ncomment accordingly."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-27T04:59:59.923Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6256899c3a34674bba6076884aedbba49fc695e4"
        },
        {
          "url": "https://git.kernel.org/stable/c/7e706d50fa119eead6376bf0ef973e8d73a96030"
        },
        {
          "url": "https://git.kernel.org/stable/c/2382971aaaef5bf85a651234c64906f59580b8be"
        },
        {
          "url": "https://git.kernel.org/stable/c/0d18ccef142f04433dfb2a0c120cf223d2b8a42c"
        },
        {
          "url": "https://git.kernel.org/stable/c/648927ceb84021a25a0fbd5673740956f318d534"
        }
      ],
      "title": "mm/slab: do not limit zeroing to orig_size when only red zoning is enabled",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64368",
    "datePublished": "2026-07-25T08:50:21.831Z",
    "dateReserved": "2026-07-19T15:36:31.783Z",
    "dateUpdated": "2026-07-27T04:59:59.923Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-64368",
      "date": "2026-07-26",
      "epss": "0.00168",
      "percentile": "0.0641"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-64368\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-07-25T10:17:19.613\",\"lastModified\":\"2026-07-27T05:16:43.820\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmm/slab: do not limit zeroing to orig_size when only red zoning is enabled\\n\\nWhen init (zeroing) on allocation is requested, for kmalloc() we\\ngenerally have to zero the full object size even if a smaller size is\\nrequested, in order to provide krealloc()\u0027s __GFP_ZERO guarantees.\\n\\nBut if we track the requested size, krealloc() uses that information to\\ndo the right thing, so we can zero only the requested size. With red\\nzoning also enabled, any extra size became part of the red zone, so it\\nmust not be zeroed and thus we must zero only the requested size.\\n\\nHowever the current check is imprecise, and will trigger also when only\\nSLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking\\nthe requested size). This means enabling red zoning alone can compromise\\nkrealloc()\u0027s __GFP_ZERO contract.\\n\\nFix this by using slub_debug_orig_size() instead, which is the exact\\ncheck for whether the requested size is tracked. We don\u0027t need to care\\nif red zoning is also enabled or not. Also update and expand the\\ncomment accordingly.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"mm/slub.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"9ce67395f5a0cdec6ce152d26bfda13b98b25c01\",\"lessThan\":\"6256899c3a34674bba6076884aedbba49fc695e4\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9ce67395f5a0cdec6ce152d26bfda13b98b25c01\",\"lessThan\":\"7e706d50fa119eead6376bf0ef973e8d73a96030\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9ce67395f5a0cdec6ce152d26bfda13b98b25c01\",\"lessThan\":\"2382971aaaef5bf85a651234c64906f59580b8be\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9ce67395f5a0cdec6ce152d26bfda13b98b25c01\",\"lessThan\":\"0d18ccef142f04433dfb2a0c120cf223d2b8a42c\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9ce67395f5a0cdec6ce152d26bfda13b98b25c01\",\"lessThan\":\"648927ceb84021a25a0fbd5673740956f318d534\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"mm/slub.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.2\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.2\",\"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-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":8.1,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.2,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0d18ccef142f04433dfb2a0c120cf223d2b8a42c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2382971aaaef5bf85a651234c64906f59580b8be\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6256899c3a34674bba6076884aedbba49fc695e4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/648927ceb84021a25a0fbd5673740956f318d534\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7e706d50fa119eead6376bf0ef973e8d73a96030\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-07-25T16:00:50Z",
      "cve": "CVE-2026-64368",
      "id": "CVE-2026-64368",
      "initial_release_date": "2026-07-25T16:00:50Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64368",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64368.json",
      "version": "2"
    }
  }
}

GHSA-M4HC-CP9R-F6RJ

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31

Details

In the Linux kernel, the following vulnerability has been resolved:

mm/slab: do not limit zeroing to orig_size when only red zoning is enabled

When init (zeroing) on allocation is requested, for kmalloc() we generally have to zero the full object size even if a smaller size is requested, in order to provide krealloc()'s __GFP_ZERO guarantees.

But if we track the requested size, krealloc() uses that information to do the right thing, so we can zero only the requested size. With red zoning also enabled, any extra size became part of the red zone, so it must not be zeroed and thus we must zero only the requested size.

However the current check is imprecise, and will trigger also when only SLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking the requested size). This means enabling red zoning alone can compromise krealloc()'s __GFP_ZERO contract.

Fix this by using slub_debug_orig_size() instead, which is the exact check for whether the requested size is tracked. We don't need to care if red zoning is also enabled or not. Also update and expand the comment accordingly.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64368"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:19Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slab: do not limit zeroing to orig_size when only red zoning is enabled\n\nWhen init (zeroing) on allocation is requested, for kmalloc() we\ngenerally have to zero the full object size even if a smaller size is\nrequested, in order to provide krealloc()\u0027s __GFP_ZERO guarantees.\n\nBut if we track the requested size, krealloc() uses that information to\ndo the right thing, so we can zero only the requested size. With red\nzoning also enabled, any extra size became part of the red zone, so it\nmust not be zeroed and thus we must zero only the requested size.\n\nHowever the current check is imprecise, and will trigger also when only\nSLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking\nthe requested size). This means enabling red zoning alone can compromise\nkrealloc()\u0027s __GFP_ZERO contract.\n\nFix this by using slub_debug_orig_size() instead, which is the exact\ncheck for whether the requested size is tracked. We don\u0027t need to care\nif red zoning is also enabled or not. Also update and expand the\ncomment accordingly.",
  "id": "GHSA-m4hc-cp9r-f6rj",
  "modified": "2026-07-25T12:31:33Z",
  "published": "2026-07-25T12:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64368"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0d18ccef142f04433dfb2a0c120cf223d2b8a42c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2382971aaaef5bf85a651234c64906f59580b8be"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6256899c3a34674bba6076884aedbba49fc695e4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/648927ceb84021a25a0fbd5673740956f318d534"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7e706d50fa119eead6376bf0ef973e8d73a96030"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-64368 (GCVE-0-2026-64368)

GHSA-M4HC-CP9R-F6RJ

Tags

Sightings

Nomenclature