{
  "threat_severity" : "Moderate",
  "public_date" : "2025-10-07T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: netfilter: conntrack: fix wrong ct->timeout value",
    "id" : "2402285",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2402285"
  },
  "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-682",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nnetfilter: conntrack: fix wrong ct->timeout value\n(struct nf_conn)->timeout is an interval before the conntrack\nconfirmed.  After confirmed, it becomes a timestamp.\nIt is observed that timeout of an unconfirmed conntrack:\n- Set by calling ctnetlink_change_timeout(). As a result,\n`nfct_time_stamp` was wrongly added to `ct->timeout` twice.\n- Get by calling ctnetlink_dump_timeout(). As a result,\n`nfct_time_stamp` was wrongly subtracted.\nCall Trace:\n<TASK>\ndump_stack_lvl\nctnetlink_dump_timeout\n__ctnetlink_glue_build\nctnetlink_glue_build\n__nfqnl_enqueue_packet\nnf_queue\nnf_hook_slow\nip_mc_output\n? __pfx_ip_finish_output\nip_send_skb\n? __pfx_dst_output\nudp_send_skb\nudp_sendmsg\n? __pfx_ip_generic_getfrag\nsock_sendmsg\nSeparate the 2 cases in:\n- Setting `ct->timeout` in __nf_ct_set_timeout().\n- Getting `ct->timeout` in ctnetlink_dump_timeout().\nPablo appends:\nUpdate ctnetlink to set up the timeout _after_ the IPS_CONFIRMED flag is\nset on, otherwise conntrack creation via ctnetlink breaks.\nNote that the problem described in this patch occurs since the\nintroduction of the nfnetlink_queue conntrack support, select a\nsufficiently old Fixes: tag for -stable kernel to pick up this fix." ],
  "statement" : "Conntrack timeout was miscomputed by mixing an interval (pre-confirm) with a timestamp (post-confirm), adding/subtracting nfct_time_stamp incorrectly. A local actor with CAP_NET_ADMIN (e.g., via ctnetlink) could cause stuck or prematurely expiring entries, impacting availability via conntrack table growth or drops.",
  "affected_release" : [ {
    "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" : "Out of support scope",
    "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",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "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-2023-53635\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-53635\nhttps://lore.kernel.org/linux-cve-announce/2025100714-CVE-2023-53635-de6f@gregkh/T" ],
  "name" : "CVE-2023-53635",
  "csaw" : false
}