{
  "threat_severity" : "Moderate",
  "public_date" : "2025-10-01T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: Linux kernel: Denial of Service via malicious MTU negotiation in TIPC",
    "id" : "2400721",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2400721"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-190",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\ntipc: do not update mtu if msg_max is too small in mtu negotiation\nWhen doing link mtu negotiation, a malicious peer may send Activate msg\nwith a very small mtu, e.g. 4 in Shuang's testing, without checking for\nthe minimum mtu, l->mtu will be set to 4 in tipc_link_proto_rcv(), then\nn->links[bearer_id].mtu is set to 4294967228, which is a overflow of\n'4 - INT_H_SIZE - EMSG_OVERHEAD' in tipc_link_mss().\nWith tipc_link.mtu = 4, tipc_link_xmit() kept printing the warning:\ntipc: Too large msg, purging xmit list 1 5 0 40 4!\ntipc: Too large msg, purging xmit list 1 15 0 60 4!\nAnd with tipc_link_entry.mtu 4294967228, a huge skb was allocated in\nnamed_distribute(), and when purging it in tipc_link_xmit(), a crash\nwas even caused:\ngeneral protection fault, probably for non-canonical address 0x2100001011000dd: 0000 [#1] PREEMPT SMP PTI\nCPU: 0 PID: 0 Comm: swapper/0 Kdump: loaded Not tainted 6.3.0.neta #19\nRIP: 0010:kfree_skb_list_reason+0x7e/0x1f0\nCall Trace:\n<IRQ>\nskb_release_data+0xf9/0x1d0\nkfree_skb_reason+0x40/0x100\ntipc_link_xmit+0x57a/0x740 [tipc]\ntipc_node_xmit+0x16c/0x5c0 [tipc]\ntipc_named_node_up+0x27f/0x2c0 [tipc]\ntipc_node_write_unlock+0x149/0x170 [tipc]\ntipc_rcv+0x608/0x740 [tipc]\ntipc_udp_recv+0xdc/0x1f0 [tipc]\nudp_queue_rcv_one_skb+0x33e/0x620\nudp_unicast_rcv_skb.isra.72+0x75/0x90\n__udp4_lib_rcv+0x56d/0xc20\nip_protocol_deliver_rcu+0x100/0x2d0\nThis patch fixes it by checking the new mtu against tipc_bearer_min_mtu(),\nand not updating mtu if it is too small.", "A flaw was found in the Linux kernel's Transparent Inter-Process Communication (TIPC) protocol. A malicious peer can exploit this by sending a specially crafted Activate message with a very small Maximum Transmission Unit (MTU) value during link MTU negotiation. This can lead to an integer overflow, causing a system crash and resulting in a Denial of Service (DoS)." ],
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2023-11-14T00:00:00Z",
    "advisory" : "RHSA-2023:7077",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8",
    "package" : "kernel-0:4.18.0-513.5.1.el8_9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2023-11-07T00:00:00Z",
    "advisory" : "RHSA-2023:6583",
    "cpe" : "cpe:/a:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-362.8.1.el9_3"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2023-11-07T00:00:00Z",
    "advisory" : "RHSA-2023:6583",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-362.8.1.el9_3"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2023-53517\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-53517\nhttps://lore.kernel.org/linux-cve-announce/2025100132-CVE-2023-53517-da77@gregkh/T" ],
  "name" : "CVE-2023-53517",
  "mitigation" : {
    "value" : "To mitigate this issue, prevent the `tipc` kernel module from loading by creating a blacklist file. This may impact functionality that relies on TIPC.\nCreate a file named `/etc/modprobe.d/blacklist-tipc.conf` with the following content:\n```\nblacklist tipc\n```\nAfter creating the file, regenerate the initramfs and reboot the system for the changes to take effect.\n```bash\ndruncate -s 0 /etc/modprobe.d/blacklist-tipc.conf\necho \"blacklist tipc\" >> /etc/modprobe.d/blacklist-tipc.conf\ndruncate -s 0 /etc/modules-load.d/tipc.conf\nmkinitrd -f /boot/initramfs-$(uname -r).img $(uname -r)\nreboot\n```\nWarning: A system reboot is required for the mitigation to be fully applied and to ensure the module is not loaded.",
    "lang" : "en:us"
  },
  "csaw" : false
}