CVE-2021-47109 neighbour: allow NUD_NOARP entries to be forced GCed

2024-03-1520:14:18

Linux

github.com

linux kernel

vulnerability

neighbour table overflow

ipv6

commit 58956317c8de

garbage collection

AI Score

7.1

Confidence

Low

EPSS

Percentile

15.5%

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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

neighbour: allow NUD_NOARP entries to be forced GCed

IFF_POINTOPOINT interfaces use NUD_NOARP entries for IPv6. It’s possible to
fill up the neighbour table with enough entries that it will overflow for
valid connections after that.

This behaviour is more prevalent after commit 58956317c8de (“neighbor:
Improve garbage collection”) is applied, as it prevents removal from
entries that are not NUD_FAILED, unless they are more than 5s old.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "58956317c8de",
        "lessThan": "d99029e6aab6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "58956317c8de",
        "lessThan": "d17d47da59f7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "58956317c8de",
        "lessThan": "ddf088d7aaaa",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "58956317c8de",
        "lessThan": "7a6b1ab7475f",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/core/neighbour.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.0"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.0",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "5.4.125",
        "versionType": "custom",
        "lessThanOrEqual": "5.4.*"
      },
      {
        "status": "unaffected",
        "version": "5.10.43",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.12.10",
        "versionType": "custom",
        "lessThanOrEqual": "5.12.*"
      },
      {
        "status": "unaffected",
        "version": "5.13",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/core/neighbour.c"
    ],
    "defaultStatus": "affected"
  }
]