CVE-2026-89602 (GCVE-0-2026-89602)
Vulnerability from cvelistv5
Published
2026-09-11 19:45
Modified
2026-10-19 08:49
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: erofs: skip sufficiently large global buffers when resizing z_erofs_gbuf_nrpages is advanced only after every global buffer has been grown. If a resize fails after some buffers were enlarged, a retry revisits those enlarged buffers. Retrying the same size then returns -ENOMEM because alloc_pages_bulk() has no pages to add and the unchanged return value is treated as a failure. Retrying an intermediate size allocates a temporary pointer array smaller than gbuf->nrpages and copies more existing pointers than the array can hold. Skip buffers that already satisfy the request. Once all remaining buffers have caught up, advancing z_erofs_gbuf_nrpages again describes the guaranteed minimum size across the pool.
References
Impacted products
Vendor Product Version
Linux Linux Version: d6db47e571dcaecaeaafa8840d00ae849ae3907b
Version: d6db47e571dcaecaeaafa8840d00ae849ae3907b
Version: d6db47e571dcaecaeaafa8840d00ae849ae3907b
Version: d6db47e571dcaecaeaafa8840d00ae849ae3907b
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/erofs/zutil.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3fbdd15d5830f52661eb78be95058d101cb0c2cb",
              "status": "affected",
              "version": "d6db47e571dcaecaeaafa8840d00ae849ae3907b",
              "versionType": "git"
            },
            {
              "lessThan": "7267557ce98ccd07faaf3bc86382448950cc4ff6",
              "status": "affected",
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              "versionType": "git"
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              "versionType": "git"
            },
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/erofs/zutil.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "lessThan": "6.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nerofs: skip sufficiently large global buffers when resizing\n\nz_erofs_gbuf_nrpages is advanced only after every global buffer has been\ngrown. If a resize fails after some buffers were enlarged, a retry\nrevisits those enlarged buffers.\n\nRetrying the same size then returns -ENOMEM because alloc_pages_bulk()\nhas no pages to add and the unchanged return value is treated as a\nfailure. Retrying an intermediate size allocates a temporary pointer\narray smaller than gbuf-\u003enrpages and copies more existing pointers than\nthe array can hold.\n\nSkip buffers that already satisfy the request. Once all remaining\nbuffers have caught up, advancing z_erofs_gbuf_nrpages again describes\nthe guaranteed minimum size across the pool."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - z_erofs_gbuf_growsize() runs only during a local EROFS mount (erofs_fc_get_tree \u2192 erofs_fc_fill_super \u2192 erofs_read_superblock \u2192 z_erofs_parse_cfgs \u2192 z_erofs_load_lz4_config) of a block, loop, or file-backed image. The LZ4 max_pclusterblks field is not parsed from a network protocol, so the vector is Local.\nAC:L - The attacker picks max_pclusterblks on two images (a large grow, then a strictly smaller size). After GFP_KERNEL alloc_pages_bulk()/vmap fails mid-loop, some per-CPU gbufs stay enlarged while z_erofs_gbuf_nrpages does not; the next intermediate mount then copies gbuf-\u003enrpages pointers into a smaller tmp_pages array with no race. A max-size image plus memory pressure makes that partial failure attacker-inducible.\nPR:N - Crafting and supplying the malicious EROFS images needs no account or capability on the target. erofs_fs_type lacks FS_USERNS_MOUNT, so the CAP_SYS_ADMIN mount is done by a victim, automounter, or container runtime (OCI/Nydus/Android image handling), matching other crafted-image EROFS CVEs.\nUI:R - mount_capable() requires CAP_SYS_ADMIN in the initial user namespace because EROFS is not FS_USERNS_MOUNT. A separate user, automounter, or container runtime must mount the attacker-supplied images before z_erofs_gbuf_growsize() runs.\nS:U - The heap overflow corrupts kmalloc objects inside the host kernel. That is standard kernel memory corruption within one security authority, not a VM escape, IOMMU bypass, or other cross-boundary impact.\nC:H - The copy loop writes a nearly page-count-sized run of struct page * values past the kmalloc tmp_pages array (up to hundreds of pointers when max_pclusterblks is 256). That slab corruption can be turned into an arbitrary-read primitive against adjacent objects, so confidentiality impact is High.\nI:H - This is a kernel heap out-of-bounds write whose length is chosen by the two image sizes, smashing adjacent slab objects with kernel page pointers. Out-of-bounds writes are exploitable for arbitrary write and control-flow hijacking, so integrity impact is High.\nA:H - Overwriting adjacent kmalloc metadata and objects causes a kernel oops or panic. Independently, retrying the same size after a partial grow treats a full tmp_pages array as -ENOMEM and leaves the pool stuck, so later EROFS mounts fail until reboot."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:49:34.524Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3fbdd15d5830f52661eb78be95058d101cb0c2cb"
        },
        {
          "url": "https://git.kernel.org/stable/c/7267557ce98ccd07faaf3bc86382448950cc4ff6"
        },
        {
          "url": "https://git.kernel.org/stable/c/7f4a89d4f0d6acaf4b756c31de48f2109a257b70"
        },
        {
          "url": "https://git.kernel.org/stable/c/a7d097cf01301c5da37927c8f26123d006f0fd8a"
        }
      ],
      "title": "erofs: skip sufficiently large global buffers when resizing",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89602",
    "datePublished": "2026-09-11T19:45:05.783Z",
    "dateReserved": "2026-09-11T19:38:34.732Z",
    "dateUpdated": "2026-10-19T08:49:34.524Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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