Linux Kernel up to 6.6.151/6.12.103/6.18.44/7.1.8 Netfilter Conntrack nf_ct_l4proto_log_invalid deadlock

CVSS Meta Temp Score
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CTI Interest Score
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7.2$0-$5k0.43-

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.6.151/6.12.103/6.18.44/7.1.8. This vulnerability affects the function nf_ct_l4proto_log_invalid of the component Netfilter Conntrack. Executing a manipulation can lead to deadlock. This vulnerability appears as CVE-2026-74624. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.6.151/6.12.103/6.18.44/7.1.8. This vulnerability affects the function nf_ct_l4proto_log_invalid of the component Netfilter Conntrack. The manipulation with an unknown input leads to a deadlock vulnerability. The CWE definition for the vulnerability is CWE-833. The product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-74624 since 08/15/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/22/2026). The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 6.6.152, 6.12.104, 6.18.45 or 7.1.9 eliminates this vulnerability. Applying the patch 63853eb20bba4e00b7cd0b8cfc19337bbaaf5037/9480fcf70a5aa9d320088a01c95df0e5e6391f4a/0424186d570aa4d1ad17f516afb86bd9eaa4f42e/c0224327b7cbed9d3198e8dbec847281053dcd06/2d19b95c9723001f214f7a47d67b09f46238f200 is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.2

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Deadlock
CWE: CWE-833 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.152/6.12.104/6.18.45/7.1.9
Patch: 63853eb20bba4e00b7cd0b8cfc19337bbaaf5037/9480fcf70a5aa9d320088a01c95df0e5e6391f4a/0424186d570aa4d1ad17f516afb86bd9eaa4f42e/c0224327b7cbed9d3198e8dbec847281053dcd06/2d19b95c9723001f214f7a47d67b09f46238f200

Timelineinfo

08/15/2026 CVE reserved
08/22/2026 +7 days Advisory disclosed
08/22/2026 +0 days VulDB entry created
08/22/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74624 (🔒)
GCVE (CVE): GCVE-0-2026-74624
GCVE (VulDB): GCVE-100-394408

Entryinfo

Created: 08/22/2026 18:24
Changes: 08/22/2026 18:24 (59)
Complete: 🔍
Cache ID: 216::103

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