GHSA-9F6G-J2JQ-6W3F

Vulnerability from github – Published: 2025-09-22 21:30 – Updated: 2026-01-20 15:31
VLAI?
Details

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 ?
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2025-39847"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-401"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-09-19T16:15:43Z",
    "severity": "MODERATE"
  },
  "details": "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.",
  "id": "GHSA-9f6g-j2jq-6w3f",
  "modified": "2026-01-20T15:31:21Z",
  "published": "2025-09-22T21:30:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39847"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0b21e9cd4559102da798bdcba453b64ecd7be7ee"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1d8b354eafb8876d8bdb1bef69c7d2438aacfbe8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/33a5bac5f14772730d2caf632ae97b6c2ee95044"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4844123fe0b853a4982c02666cb3fd863d701d50"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/631fc8ab5beb9e0ec8651fb9875b9a968e7b4ae4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/85c1c86a67e09143aa464e9bf09c397816772348"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/87a35a36742df328d0badf4fbc2e56061c15846c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9ca6a040f76c0b149293e430dabab446f3fc8ab7"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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