GHSA-9CCH-CJJM-3M2C

Vulnerability from github – Published: 2026-08-15 15:30 – Updated: 2026-08-19 18:32
VLAI
Details

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

net: do not send ICMP/NDISC Redirects when peer allocation fails

When inet_getpeer_v4() or inet_getpeer_v6() fails to allocate a peer entry under memory pressure or tree size caps, redirect handlers previously fell back to sending un-rate-limited ICMP/NDISC Redirect messages.

In IPv4, ip_rt_send_redirect() called icmp_send() directly when peer == NULL. In IPv6, ip6_forward() and ndisc_send_redirect() passed a NULL peer into inet_peer_xrlim_allow(), which returned true when peer == NULL.

Because ICMP/NDISC Redirects are not part of the default global rate limit mask (sysctl_icmp_ratemask), sending redirects when peer == NULL creates an un-rate-limited ICMP packet storm.

Fix this by failing closed in ip_rt_send_redirect(), ip6_forward(), and ndisc_send_redirect() when peer is NULL.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-74550"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T13:18:00Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: do not send ICMP/NDISC Redirects when peer allocation fails\n\nWhen inet_getpeer_v4() or inet_getpeer_v6() fails to allocate a peer entry\nunder memory pressure or tree size caps, redirect handlers previously fell\nback to sending un-rate-limited ICMP/NDISC Redirect messages.\n\nIn IPv4, ip_rt_send_redirect() called icmp_send() directly when peer == NULL.\nIn IPv6, ip6_forward() and ndisc_send_redirect() passed a NULL peer into\ninet_peer_xrlim_allow(), which returned true when peer == NULL.\n\nBecause ICMP/NDISC Redirects are not part of the default global rate limit\nmask (sysctl_icmp_ratemask), sending redirects when peer == NULL creates\nan un-rate-limited ICMP packet storm.\n\nFix this by failing closed in ip_rt_send_redirect(), ip6_forward(), and\nndisc_send_redirect() when peer is NULL.",
  "id": "GHSA-9cch-cjjm-3m2c",
  "modified": "2026-08-19T18:32:31Z",
  "published": "2026-08-15T15:30:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74550"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/21666f7af49a90ef44d474916b8ef4402dfd74f5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5ec5f00fc606a6df8434948c4552b3cb1176595d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/828f6670d110ff2bf44c743037b38badc315704c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c0adf8b4247bcc5a145a25c1929006eb392580bb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dbc3791e3b2472e1ccc08947e0f83b443470ff4f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5ecaa7ea7686fa7ecdb6affc9d3a9a42e4524b1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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