netfilter: nf_conntrack: destroy stale expectfn expectations on unregister
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
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
- Not stated in this record
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
No explicit severity was provided.
- Event
- #28451 · Revision 1
- Added to Heist Feed
- Publisher date