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netfilter: nf_conntrack: destroy stale expectfn expectations on unregister

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: destroy stale expectfn expectations on unregister NAT helpers such as nf_nat_h323 store a raw pointer to module text in exp->expectfn (e.g. ip_nat_q931_expect). nf_ct_helper_expectfn_unregister() only unlinks the callback descriptor and never walks the expectation table, so an expectation pending at module removal survives with a dangling exp->expectfn into freed module text. When the expected connection arrives, init_conntrack() invokes exp->expectfn(), now a stale pointer into the unloaded module. Reproduced on a KASAN build by loading the H.323 helpers, creating a Q.931 expectation, unloading nf_nat_h323, then connecting to the expected port: Oops: int3: 0000 [#1] SMP KASAN NOPTI RIP: 0010:0xffffffffa06102d1 init_conntrack.isra.0 (net/netfilter/nf_conntrack_core.c:1862) nf_conntrack_in (net/netfilter/nf_conntrack_core.c:2049) ipv4_conntrack_local (net/netfilter/nf_conntrack_proto.c:223) nf_hook_slow (net/netfilter/core.c:619) __ip_local_out (net/ipv4/ip_output.c:120) __tcp_transmit_skb (net/ipv4/tcp_output.c:1715) tcp_connect (net/ipv4/tcp_output.c:4374) tcp_v4_connect (net/ipv4/tcp_ipv4.c:345) __sys_connect (net/socket.c:2167) Modules linked in: nf_conntrack_h323 [last unloaded: nf_nat_h323] Reaching the dangling state requires CAP_SYS_MODULE in the initial user namespace to remove a NAT helper that still has live expectations, so this is a robustness fix; leaving an expectation p

Announced Source revision 1
Original source ↗

CVE-2026-53349

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-53349

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "f587de0e2feb9eb9b94f98d0a7b7437e4d6617b4",
        "lessThan": "fbfde85308b99938a6092c48753214d190ece48d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f587de0e2feb9eb9b94f98d0a7b7437e4d6617b4",
        "lessThan": "29d8cc44bbdf7b83a1929912214afe6643c1b4f1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f587de0e2feb9eb9b94f98d0a7b7437e4d6617b4",
        "lessThan": "f92c90a2a3e6ff6f9f7fe88fde9004b4ca8f956d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f587de0e2feb9eb9b94f98d0a7b7437e4d6617b4",
        "lessThan": "9d017671dcfcec23321fb7962dea624f9e71ddb1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f587de0e2feb9eb9b94f98d0a7b7437e4d6617b4",
        "lessThan": "bf8c0b5dd203be94c2ad50e264cec19267c6bd39",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f587de0e2feb9eb9b94f98d0a7b7437e4d6617b4",
        "lessThan": "c3009418f9fa1dcb3eb86f4d8c92583537b5faa3",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "include/net/netfilter/nf_conntrack_helper.h",
      "net/ipv4/netfilter/nf_nat_h323.c",
      "net/netfilter/nf_conntrack_helper.c",
      "net/netfilter/nf_nat_core.c",
      "net/netfilter/nf_nat_sip.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.20"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.20",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.1.176",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.143",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.94",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.36",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.0.13",
        "versionType": "semver",
        "lessThanOrEqual": "7.0.*"
      },
      {
        "status": "unaffected",
        "version": "7.1",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/net/netfilter/nf_conntrack_helper.h",
      "net/ipv4/netfilter/nf_nat_h323.c",
      "net/netfilter/nf_conntrack_helper.c",
      "net/netfilter/nf_nat_core.c",
      "net/netfilter/nf_nat_sip.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-53349

Source reference: /cveMetadata/cveId

Publisher severity

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Event
#28451 · Revision 1
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