{
  "threat_severity" : "Moderate",
  "public_date" : "2026-05-01T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: netfilter: nf_conntrack_helper: pass helper to expect cleanup",
    "id" : "2464369",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2464369"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.1",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-459",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nnetfilter: nf_conntrack_helper: pass helper to expect cleanup\nnf_conntrack_helper_unregister() calls nf_ct_expect_iterate_destroy()\nto remove expectations belonging to the helper being unregistered.\nHowever, it passes NULL instead of the helper pointer as the data\nargument, so expect_iter_me() never matches any expectation and all\nof them survive the cleanup.\nAfter unregister returns, nfnl_cthelper_del() frees the helper\nobject immediately.  Subsequent expectation dumps or packet-driven\ninit_conntrack() calls then dereference the freed exp->helper,\ncausing a use-after-free.\nPass the actual helper pointer so expectations referencing it are\nproperly destroyed before the helper object is freed.\nBUG: KASAN: slab-use-after-free in string+0x38f/0x430\nRead of size 1 at addr ffff888003b14d20 by task poc/103\nCall Trace:\nstring+0x38f/0x430\nvsnprintf+0x3cc/0x1170\nseq_printf+0x17a/0x240\nexp_seq_show+0x2e5/0x560\nseq_read_iter+0x419/0x1280\nproc_reg_read+0x1ac/0x270\nvfs_read+0x179/0x930\nksys_read+0xef/0x1c0\nFreed by task 103:\nThe buggy address is located 32 bytes inside of\nfreed 192-byte region [ffff888003b14d00, ffff888003b14dc0)", "A flaw was found in the Linux kernel's netfilter subsystem, specifically within the `nf_conntrack_helper`. When a connection tracking helper is unregistered, its associated expectations are not properly cleaned up. This oversight can lead to a use-after-free vulnerability, where the system attempts to access memory that has already been released. A local attacker could exploit this to cause a system crash, resulting in a Denial of Service (DoS), or potentially achieve privilege escalation." ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Under investigation",
    "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" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-43027\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-43027\nhttps://lore.kernel.org/linux-cve-announce/2026050159-CVE-2026-43027-5711@gregkh/T" ],
  "name" : "CVE-2026-43027",
  "csaw" : false
}