CVE-2026-74624 (GCVE-0-2026-74624)
Vulnerability from cvelistv5
Published
2026-08-22 15:32
Modified
2026-08-25 05:40
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack: defer invalid log until after unlock
TCP and SCTP conntrack paths can emit invalid-packet logs while ct->lock
is still held.
When invalid logging is routed to nfnetlink_log and conntrack export is
enabled, the log path can re-enter conntrack netlink glue and dump the
same conntrack again. Protocol attribute dumping may take ct->lock, so
logging while holding that lock can deadlock.
Defer the TCP invalid logs by storing only the minimal log context while
ct->lock is held and emitting the log after unlocking. Also make the TCP
timeout-lowering invalid path return whether a log is needed, then emit
that log after unlocking.
Do the same for the SCTP invalid state-transition log that can be reached
while ct->lock is held.
Add a lockdep assertion to nf_ct_l4proto_log_invalid() so future callers
that log invalid conntracks while holding ct->lock are caught outside TCP
and SCTP as well.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: d9a6f0d0df1899ff9086a57abc600e414f4b8cdd Version: d9a6f0d0df1899ff9086a57abc600e414f4b8cdd Version: d9a6f0d0df1899ff9086a57abc600e414f4b8cdd Version: d9a6f0d0df1899ff9086a57abc600e414f4b8cdd Version: d9a6f0d0df1899ff9086a57abc600e414f4b8cdd Version: d9a6f0d0df1899ff9086a57abc600e414f4b8cdd |
||
{
"containers": {
"cna": {
"affected": [
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"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/netfilter/nf_conntrack_proto.c",
"net/netfilter/nf_conntrack_proto_sctp.c",
"net/netfilter/nf_conntrack_proto_tcp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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]
},
{
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"product": "Linux",
"programFiles": [
"net/netfilter/nf_conntrack_proto.c",
"net/netfilter/nf_conntrack_proto_sctp.c",
"net/netfilter/nf_conntrack_proto_tcp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.1"
},
{
"lessThan": "6.1",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.1.184",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.184",
"versionStartIncluding": "6.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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{
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{
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},
{
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"versionStartIncluding": "6.1",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack: defer invalid log until after unlock\n\nTCP and SCTP conntrack paths can emit invalid-packet logs while ct-\u003elock\nis still held.\n\nWhen invalid logging is routed to nfnetlink_log and conntrack export is\nenabled, the log path can re-enter conntrack netlink glue and dump the\nsame conntrack again. Protocol attribute dumping may take ct-\u003elock, so\nlogging while holding that lock can deadlock.\n\nDefer the TCP invalid logs by storing only the minimal log context while\nct-\u003elock is held and emitting the log after unlocking. Also make the TCP\ntimeout-lowering invalid path return whether a log is needed, then emit\nthat log after unlocking.\n\nDo the same for the SCTP invalid state-transition log that can be reached\nwhile ct-\u003elock is held.\n\nAdd a lockdep assertion to nf_ct_l4proto_log_invalid() so future callers\nthat log invalid conntracks while holding ct-\u003elock are caught outside TCP\nand SCTP as well."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The flaw is hit in nf_conntrack_tcp_packet()/nf_conntrack_sctp_packet() from the NF_INET_PRE_ROUTING and LOCAL_OUT netfilter hooks on received or forwarded TCP/SCTP traffic, so a remote peer can trigger invalid conntrack handling with crafted packets to internet-facing NAT gateways, routers, and servers.\nAC:L - Once nf_conntrack_log_invalid, nflog binding, and NFULNL_CFG_F_CONNTRACK are enabled (the CVE-scoped configuration on monitored firewalls), an attacker deterministically deadlocks by sending invalid-sequence TCP or invalid-state SCTP packets on tracked flows without races or special memory layout.\nPR:N - Triggering the vulnerable conntrack path requires only the ability to send TCP/SCTP packets to a host already running connection tracking with invalid logging; no local account, CAP_NET_ADMIN, or netlink configuration privileges are needed on the attacker side.\nUI:N - Exploitation is driven entirely by network packet delivery and softirq packet processing; no victim must open files, mount filesystems, or perform any interactive action beyond normal network connectivity to the target.\nS:U - The deadlock confines impact to the same kernel networking authority processing the packet; it does not cross VM, container, or IOMMU boundaries to compromise a separate security domain.\nC:N - This is a recursive spinlock deadlock in conntrack invalid logging with no memory corruption, out-of-bounds access, use-after-free, or information-disclosure primitive.\nI:N - The bug causes a lock re-entry hang during logging only; it does not modify kernel or user data, provide arbitrary write primitives, or enable code execution.\nA:H - Re-acquiring ct-\u003elock while it is held deadlocks packet processing on the affected CPU in softirq context, can stall networking on that core, and may escalate to soft lockup or watchdog-induced kernel panic under sustained attack."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-25T05:40:47.114Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/ca97360eba4b3dc67f1804625542f4ccc774242a"
},
{
"url": "https://git.kernel.org/stable/c/63853eb20bba4e00b7cd0b8cfc19337bbaaf5037"
},
{
"url": "https://git.kernel.org/stable/c/9480fcf70a5aa9d320088a01c95df0e5e6391f4a"
},
{
"url": "https://git.kernel.org/stable/c/0424186d570aa4d1ad17f516afb86bd9eaa4f42e"
},
{
"url": "https://git.kernel.org/stable/c/c0224327b7cbed9d3198e8dbec847281053dcd06"
},
{
"url": "https://git.kernel.org/stable/c/2d19b95c9723001f214f7a47d67b09f46238f200"
}
],
"title": "netfilter: nf_conntrack: defer invalid log until after unlock",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74624",
"datePublished": "2026-08-22T15:32:07.193Z",
"dateReserved": "2026-08-15T05:44:03.921Z",
"dateUpdated": "2026-08-25T05:40:47.114Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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