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CVE-2026-80656

Estado: RecibidaAlta (7.8)—

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

hfsplus: Add a sanity check for btree node size

Syzbot reported an uninit-value bug in [1] with a corrupted HFS+ image, during the file system mounting process, specifically while loading the catalog, a corrupted node_size value of 1 caused the rec_off argument passed to hfs_bnode_read_u16() (within hfs_bnode_find()) to be excessively large. Consequently, the function failed to return a valid value to initialize the off variable, triggering the bug [1].

Every node starts from BTree node descriptor: struct hfs_bnode_desc. So, the size of node cannot be lesser than that.

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However, technical specification declares that: "The node size (which is expressed in bytes) must be power of two, from 512 through 32,768, inclusive." Add a check for btree node size base on technical specification.

Detalles técnicos trazas, registros y código del informe original
[1]
BUG: KMSAN: uninit-value in hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584
 hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584
 hfsplus_btree_open+0x169a/0x1e40 fs/hfsplus/btree.c:382
 hfsplus_fill_super+0x111f/0x2770 fs/hfsplus/super.c:553
 get_tree_bdev_flags+0x6e6/0x920 fs/super.c:1694
 get_tree_bdev+0x38/0x50 fs/super.c:1717
 hfsplus_get_tree+0x35/0x40 fs/hfsplus/super.c:709
 vfs_get_tree+0xb3/0x5d0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]

CVSS

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad local (AV:L, PR:L) en kernel Linux sin interacción: escalada de privilegios por corrupción de imagen HFS+. Causa DoS (crash) e acceso a memoria no inicializada durante montaje del sistema de ficheros.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

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-2026-80656",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "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": "8ad2c6a36ac4328072377906a47ea0bff11e4032",
              "lessThan": "306265eb9384d2c224f1b14d83a29323f0eab6d1",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8ad2c6a36ac4328072377906a47ea0bff11e4032",
              "lessThan": "3f95e2661574ff13f099dd13456751933c280628",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/hfsplus/btree.c",
            "include/linux/hfs_common.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.1",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/hfsplus/btree.c",
            "include/linux/hfs_common.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-28T08:16:50.700",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/306265eb9384d2c224f1b14d83a29323f0eab6d1",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3f95e2661574ff13f099dd13456751933c280628",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfsplus: Add a sanity check for btree node size\n\nSyzbot reported an uninit-value bug in [1] with a corrupted HFS+ image,\nduring the file system mounting process, specifically while loading the\ncatalog, a corrupted node_size value of 1 caused the rec_off argument\npassed to hfs_bnode_read_u16() (within hfs_bnode_find()) to be excessively\nlarge. Consequently, the function failed to return a valid value to\ninitialize the off variable, triggering the bug [1].\n\nEvery node starts from BTree node descriptor: struct hfs_bnode_desc.\nSo, the size of node cannot be lesser than that. However, technical\nspecification declares that: \"The node size (which is expressed in bytes)\nmust be power of two, from 512 through 32,768, inclusive.\" Add a check\nfor btree node size base on technical specification.\n\n[1]\nBUG: KMSAN: uninit-value in hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584\n hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584\n hfsplus_btree_open+0x169a/0x1e40 fs/hfsplus/btree.c:382\n hfsplus_fill_super+0x111f/0x2770 fs/hfsplus/super.c:553\n get_tree_bdev_flags+0x6e6/0x920 fs/super.c:1694\n get_tree_bdev+0x38/0x50 fs/super.c:1717\n hfsplus_get_tree+0x35/0x40 fs/hfsplus/super.c:709\n vfs_get_tree+0xb3/0x5d0 fs/super.c:1754\n fc_mount fs/namespace.c:1193 [inline]"
    }
  ],
  "lastModified": "2026-08-29T07:16:48.437",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}