{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-53189",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2023-53189"
  ],
  "published": "2025-09-15T14:10:32Z",
  "summary": "ipv6/addrconf: fix a potential refcount underflow for idev",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6/addrconf: fix a potential refcount underflow for idev\n\nNow in addrconf_mod_rs_timer(), reference idev depends on whether\nrs_timer is not pending. Then modify rs_timer timeout.\n\nThere is a time gap in [1], during which if the pending rs_timer\nbecomes not pending. It will miss to hold idev, but the rs_timer\nis activated. Thus rs_timer callback function addrconf_rs_timer()\nwill be executed and put idev later without holding idev. A refcount\nunderflow issue for idev can be caused by this.\n\n\tif (!timer_pending(&idev->rs_timer))\n\t\tin6_dev_hold(idev);\n\t\t  <--------------[1]\n\tmod_timer(&idev->rs_timer, jiffies + when);\n\nTo fix the issue, hold idev if mod_timer() return 0.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.21-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v6",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7l",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v8",
            "binary_version": "1:6.1.21-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.21-1+rpt1": {
            "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed",
            "upstream_version": "6.1.21",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.40"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-53189"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c6395e32935d35e6f935e7caf1c2dac5a95943b4"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/df62fdcd004afa72ecbed0e862ebb983acd3aa57"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c7eeba47058532f6077d6a658e38b6698f6ae71a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2ad31ce40e8182860b631e37209e93e543790b7c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/82abd1c37d3bf2a2658b34772c17a25a6f9cca42"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/436b7cc7eae7851c184b671ed7a4a64c750b86f7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1f656e483eb4733d62f18dfb206a49b78f60f495"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/06a0716949c22e2aefb648526580671197151acc"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:24:39Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The bug is only reachable via local IPv6 addrconf paths that call addrconf_mod_rs_timer()\u2014DAD completion on interface bring-up and inet6_set_iftoken() via rtnetlink\u2014not via processing remote packets.\nAC:L - An attacker who can configure the netns controls both sides of the race: they can arm the RS timer, set a very short router_solicitation_interval via netns sysctl, and spam set_iftoken/ifup to hit the timer_pending-to-mod_timer window as the timer fires.\nPR:L - Triggering requires CAP_NET_ADMIN for interface/token/sysctl configuration, which an unprivileged user can obtain inside a user+network namespace; it does not require host-init-namespace root.\nUI:N - No victim interaction is needed; the attacker performs all interface and netlink operations themselves.\nS:U - Impact is memory corruption within the same kernel networking authority (inet6_dev UAF/refcount corruption), not a cross-boundary escape.\nC:H - The missed in6_dev_hold lets addrconf_rs_timer() put without a matching hold, which can free or leave inet6_dev at refcnt 0 while still reachable via the device, enabling a use-after-free read primitive.\nI:H - The same inet6_dev use-after-free/refcount corruption can be exploited for heap reuse and arbitrary write/control-flow hijack against the kernel network stack.\nA:H - Refcount underflow or premature destruction of inet6_dev leads to kernel WARN/oops, unstable networking state, or crash when the dangling idev is used."
    }
  }
}