{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.85-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.19.14-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  ipv4: nexthop: allocate skb dynamically in rtm_get_nexthop()  When querying a nexthop object via RTM_GETNEXTHOP, the kernel currently allocates a fixed-size skb using NLMSG_GOODSIZE. While sufficient for single nexthops and small Equal-Cost Multi-Path groups, this fixed allocation fails for large nexthop groups like 512 nexthops.  This results in the following warning splat:   WARNING: net/ipv4/nexthop.c:3395 at rtm_get_nexthop+0x176/0x1c0, CPU#20: rep/4608  [...]  RIP: 0010:rtm_get_nexthop (net/ipv4/nexthop.c:3395)  [...]  Call Trace:   \u003cTASK\u003e   rtnetlink_rcv_msg (net/core/rtnetlink.c:6989)   netlink_rcv_skb (net/netlink/af_netlink.c:2550)   netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)   netlink_sendmsg (net/netlink/af_netlink.c:1894)   ____sys_sendmsg (net/socket.c:721 net/socket.c:736 net/socket.c:2585)   ___sys_sendmsg (net/socket.c:2641)   __sys_sendmsg (net/socket.c:2671)   do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)   \u003c/TASK\u003e  Fix this by allocating the size dynamically using nh_nlmsg_size() and using nlmsg_new(), this is consistent with nexthop_notify() behavior. In addition, adjust nh_nlmsg_size_grp() so it calculates the size needed based on flags passed. While at it, also add the size of NHA_FDB for nexthop group size calculation as it was missing too.  This cannot be reproduced via iproute2 as the group size is currently limited and the command fails as follows:  addattr_l ERROR: message exceeded bound of 1048",
  "id": "DEBIAN-CVE-2026-31531",
  "modified": "2026-09-14T16:47:45.844564311Z",
  "published": "2026-04-23T12:17:01.820Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-31531"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-31531"
  ]
}