CVE-2025-40306

Estado: AplazadaAlta (7.8)—

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

orangefs: fix xattr related buffer overflow...

Willy Tarreau <w@1wt.eu> forwarded me a message from Disclosure <disclosure@aisle.com> with the following warning:

> The helper `xattr_key()` uses the pointer variable in the loop condition > rather than dereferencing it. As `key` is incremented, it remains non-NULL > (until it runs into unmapped memory), so the loop does not terminate on > valid C strings and will walk memory indefinitely, consuming CPU or hanging > the thread.

I easily reproduced this with setfattr and getfattr, causing a kernel oops, hung user processes and corrupted orangefs files. Disclosure sent along a diff (not a patch) with a suggested fix, which I based this patch on.

Leer descripción completaMostrar menos

After xattr_key started working right, xfstest generic/069 exposed an xattr related memory leak that lead to OOM. xattr_key returns a hashed key. When adding xattrs to the orangefs xattr cache, orangefs used hash_add, a kernel hashing macro. hash_add also hashes the key using hash_log which resulted in additions to the xattr cache going to the wrong hash bucket. generic/069 tortures a single file and orangefs does a getattr for the xattr "security.capability" every time. Orangefs negative caches on xattrs which includes a kmalloc. Since adds to the xattr cache were going to the wrong bucket, every getattr for "security.capability" resulted in another kmalloc, none of which were ever freed.

I changed the two uses of hash_add to hlist_add_head instead and the memory leak ceased and generic/069 quit throwing furniture.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.16%
Percentil entre todas las CVEs puntuadas: 5
Fecha de la puntuación: 6/10/2026

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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %
Impacto secundarioT1565.001 Stored Data Manipulationimpact70 %

Vulnerabilidad de buffer overflow en kernel Linux con privilegios locales (PR:L) que causa oops del kernel, denial of service por consumo de CPU/memoria y corrupción de ficheros orangefs.

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 Program Restrict File and Directory Permissions Remote Data Storage Filter Network Traffic Execution Prevention Encrypt Sensitive Information

Tecnologías afectadas (1)

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

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2025-40306",
  "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
      }
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      "affectedData": [
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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              "status": "unaffected",
              "version": "5.15.197",
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              "version": "6.1.159",
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              "status": "unaffected",
              "version": "6.6.117",
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            },
            {
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          ],
          "programFiles": [
            "fs/orangefs/xattr.c"
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  "published": "2025-12-08T01:16:02.820",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\norangefs: fix xattr related buffer overflow...\n\nWilly Tarreau <w@1wt.eu> forwarded me a message from\nDisclosure <disclosure@aisle.com> with the following\nwarning:\n\n> The helper `xattr_key()` uses the pointer variable in the loop condition\n> rather than dereferencing it. As `key` is incremented, it remains non-NULL\n> (until it runs into unmapped memory), so the loop does not terminate on\n> valid C strings and will walk memory indefinitely, consuming CPU or hanging\n> the thread.\n\nI easily reproduced this with setfattr and getfattr, causing a kernel\noops, hung user processes and corrupted orangefs files. Disclosure\nsent along a diff (not a patch) with a suggested fix, which I based\nthis patch on.\n\nAfter xattr_key started working right, xfstest generic/069 exposed an\nxattr related memory leak that lead to OOM. xattr_key returns\na hashed key.  When adding xattrs to the orangefs xattr cache, orangefs\nused hash_add, a kernel hashing macro. hash_add also hashes the key using\nhash_log which resulted in additions to the xattr cache going to the wrong\nhash bucket. generic/069 tortures a single file and orangefs does a\ngetattr for the xattr \"security.capability\" every time. Orangefs\nnegative caches on xattrs which includes a kmalloc. Since adds to the\nxattr cache were going to the wrong bucket, every getattr for\n\"security.capability\" resulted in another kmalloc, none of which were\never freed.\n\nI changed the two uses of hash_add to hlist_add_head instead\nand the memory leak ceased and generic/069 quit throwing furniture."
    }
  ],
  "lastModified": "2026-07-30T06:24:28.023",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}