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CVE-2025-39847

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: ppp: fix memory leak in pad_compress_skb If alloc_skb() fails in pad_compress_skb(), it returns NULL without releasing the old skb. The caller does: skb = pad_compress_skb(ppp, skb); if (!skb) goto drop; drop: kfree_skb(skb); When pad_compress_skb() returns NULL, the reference to the old skb is lost and kfree_skb(skb) ends up doing nothing, leading to a memory leak. Align pad_compress_skb() semantics with realloc(): only free the old skb if allocation and compression succeed. At the call site, use the new_skb variable so the original skb is not lost when pad_compress_skb() fails.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-09-19 16:15:43.513000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON 
{
  "id": "CVE-2025-39847",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-09-19T16:15:43.513",
  "lastModified": "2026-10-19T21:10:00.160",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nppp: fix memory leak in pad_compress_skb\n\nIf alloc_skb() fails in pad_compress_skb(), it returns NULL without\nreleasing the old skb. The caller does:\n\n    skb = pad_compress_skb(ppp, skb);\n    if (!skb)\n        goto drop;\n\ndrop:\n    kfree_skb(skb);\n\nWhen pad_compress_skb() returns NULL, the reference to the old skb is\nlost and kfree_skb(skb) ends up doing nothing, leading to a memory leak.\n\nAlign pad_compress_skb() semantics with realloc(): only free the old\nskb if allocation and compression succeed.  At the call site, use the\nnew_skb variable so the original skb is not lost when pad_compress_skb()\nfails."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nppp: corrige una fuga de memoria en pad_compress_skb\n\nSi alloc_skb() falla en pad_compress_skb(), devuelve NULL sin liberar el skb antiguo. El llamador hace:\n\n    skb = pad_compress_skb(ppp, skb);\n    if (!skb)\n        goto drop;\n\ndrop:\n    kfree_skb(skb);\n\nCuando pad_compress_skb() devuelve NULL, la referencia al skb antiguo se pierde y kfree_skb(skb) termina sin hacer nada, lo que lleva a una fuga de memoria.\n\nAlinea la semántica de pad_compress_skb() con realloc(): solo libera el skb antiguo si la asignación y la compresión tienen éxito. En el sitio de la llamada, usa la variable new_skb para que el skb original no se pierda cuando pad_compress_skb() falla."
    }
  ],
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              "lessThanOrEqual": "6.16.*",
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            },
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              "version": "6.17",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
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      "affectedData": [
        {
          "vendor": "Siemens",
          "product": "SIMATIC CN 4100",
          "defaultStatus": "unknown",
          "versions": [
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              "version": "0",
              "lessThan": "V5.0",
              "versionType": "custom",
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  "metrics": {
    "cvssMetricV31": [
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        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-401"
        }
      ]
    }
  ],
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