CVE-2023-53635 (GCVE-0-2023-53635)

Vulnerability from cvelistv5 – Published: 2025-10-07 15:19 – Updated: 2026-08-05 09:15
VLAI
Title
netfilter: conntrack: fix wrong ct->timeout value
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: fix wrong ct->timeout value (struct nf_conn)->timeout is an interval before the conntrack confirmed. After confirmed, it becomes a timestamp. It is observed that timeout of an unconfirmed conntrack: - Set by calling ctnetlink_change_timeout(). As a result, `nfct_time_stamp` was wrongly added to `ct->timeout` twice. - Get by calling ctnetlink_dump_timeout(). As a result, `nfct_time_stamp` was wrongly subtracted. Call Trace: <TASK> dump_stack_lvl ctnetlink_dump_timeout __ctnetlink_glue_build ctnetlink_glue_build __nfqnl_enqueue_packet nf_queue nf_hook_slow ip_mc_output ? __pfx_ip_finish_output ip_send_skb ? __pfx_dst_output udp_send_skb udp_sendmsg ? __pfx_ip_generic_getfrag sock_sendmsg Separate the 2 cases in: - Setting `ct->timeout` in __nf_ct_set_timeout(). - Getting `ct->timeout` in ctnetlink_dump_timeout(). Pablo appends: Update ctnetlink to set up the timeout _after_ the IPS_CONFIRMED flag is set on, otherwise conntrack creation via ctnetlink breaks. Note that the problem described in this patch occurs since the introduction of the nfnetlink_queue conntrack support, select a sufficiently old Fixes: tag for -stable kernel to pick up this fix.
Severity
8.2 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: a4b4766c3cebb4018167e06b863d8e95b7274757 , < 80c5ba0078e20d926d11d0778f9a43902664ebf0 (git)
Affected: a4b4766c3cebb4018167e06b863d8e95b7274757 , < ff5e4ac8dd7be7f1faba955c5779a68571eeb0f8 (git)
Affected: a4b4766c3cebb4018167e06b863d8e95b7274757 , < f612ae1ab4793701caf39386fb3b7f4b3ef44e48 (git)
Affected: a4b4766c3cebb4018167e06b863d8e95b7274757 , < 73db1b8f2bb6725b7391e85aab41fdf592b3c0c1 (git)
guessed Create a notification for this product.
Linux Linux Affected: 4.4
Unaffected: 0 , < 4.4 (semver)
Unaffected: 6.1.28 , ≤ 6.1.* (semver)
Unaffected: 6.2.15 , ≤ 6.2.* (semver)
Unaffected: 6.3.2 , ≤ 6.3.* (semver)
Unaffected: 6.4 , ≤ * (original_commit_for_fix)
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: conntrack: fix wrong ct-\u003etimeout value\n\n(struct nf_conn)-\u003etimeout is an interval before the conntrack\nconfirmed.  After confirmed, it becomes a timestamp.\n\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-\u003etimeout` twice.\n- Get by calling ctnetlink_dump_timeout(). As a result,\n  `nfct_time_stamp` was wrongly subtracted.\n\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl\n ctnetlink_dump_timeout\n __ctnetlink_glue_build\n ctnetlink_glue_build\n __nfqnl_enqueue_packet\n nf_queue\n nf_hook_slow\n ip_mc_output\n ? __pfx_ip_finish_output\n ip_send_skb\n ? __pfx_dst_output\n udp_send_skb\n udp_sendmsg\n ? __pfx_ip_generic_getfrag\n sock_sendmsg\n\nSeparate the 2 cases in:\n- Setting `ct-\u003etimeout` in __nf_ct_set_timeout().\n- Getting `ct-\u003etimeout` in ctnetlink_dump_timeout().\n\nPablo appends:\n\nUpdate ctnetlink to set up the timeout _after_ the IPS_CONFIRMED flag is\nset on, otherwise conntrack creation via ctnetlink breaks.\n\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."
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                "value": "NVD-CWE-noinfo"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-04T19:18:44+00:00",
      "cve": "CVE-2023-53635",
      "id": "CVE-2023-53635",
      "initial_release_date": "2023-01-01T00:00:00+00:00",
      "product_status:known_affected": "170",
      "product_status:known_not_affected": "104",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: netfilter: conntrack: fix wrong ct-\u003etimeout value",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-53635.json",
      "version": "3"
    }
  }
}



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