7.5
HIGH
CVSS 3.1
CVE-2026-72418
netfilter: nf_conncount: prevent connlimit drops for early confirmed ct
Overview
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conncount: prevent connlimit drops for early confirmed ct Commit 69894e5b4c5e ("netfilter: nft_connlimit: update the count if add was skipped") introduced a regression where packets for valid connections are dropped when using connlimit for soft-limiting scenarios. The issue occurs when a new connection reuses a socket currently in the TIME_WAIT state. In this scenario, the connection tracking entry is evaluated as already confirmed. Previously, __nf_conncount_add() assumed that if a connection was confirmed and did not originate from the loopback interface, it should skip the addition and return -EEXIST. Skipping the addition triggers a garbage collection run that cleans up the TIME_WAIT connection. Consequently, the active connection count drops to 0, which xt_connlimit mishandles, leading to the false rejection of the perfectly valid new connection. Fix this by replacing the interface check with protocol-agnostic state checks. We now skip the tree insertion and preserve the lockless garbage collection optimization only if the connection is IPS_ASSURED. This allows early-confirmed setup packets (such as reused TIME_WAIT sockets or locally generated SYN-ACKs) to be properly evaluated and counted without falsely dropping. The goto check_connections path is maintained to ensure these setup packets are deduplicated correctly. This has been tested with slowhttptest and HTTP server configured locally to ensure we are not breaking soft-limiting scenarios for local or external connections. In addition, it was tested with a OVS zone limit too.
Details
INFO
Published Date :
Aug. 15, 2026, 6:22 a.m.
Last Modified :
Aug. 17, 2026, 6:19 a.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
Update the Linux kernel to prevent connection limit issues causing packet drops.
- Apply the kernel patch that addresses the nf_conncount regression.
- Update the Linux kernel to the latest stable version.
- Verify the connection limit functionality after the update.
References
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-72418.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-72418 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-72418
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-72418 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-72418 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '460c112e1d887b58b06b56e8e0230058906ff2c3', 'lessThan': '000ac6830b56499d6b65fd91486ce6689eb02be4', 'versionType': 'git'}, {'status': 'affected', 'version': '53bc0ac47f4f7621c991807bc90e01df49561ac8', 'lessThan': 'cbe2d14a7c5b1fc71821fbfee5c4963917411e92', 'versionType': 'git'}, {'status': 'affected', 'version': 'ca8b4d1d6304a84ce2016fa2fe9a114b9607b839', 'lessThan': '3793d24de224943e0a6016bbeffb6f5c4cea2e3d', 'versionType': 'git'}, {'status': 'affected', 'version': '8286c02fe9100330475331253fc590f047963f90', 'lessThan': 'abef7f817217fcb62c11821d6b895063eadb2828', 'versionType': 'git'}, {'status': 'affected', 'version': 'b29ddccf36946a90323486221f39e9f88cc01b8e', 'lessThan': 'ebfe8249ba79e4ff0f1e3aad8787b992ef27f026', 'versionType': 'git'}, {'status': 'affected', 'version': '77ea3d8ac3d3d59b5ac9ad639e4ba107c0f2ff1e', 'lessThan': '329f2626ee5cb8fafdf6b58b624311529c57cb45', 'versionType': 'git'}, {'status': 'affected', 'version': '69894e5b4c5e28cda5f32af33d4a92b7a4b93b0e', 'lessThan': 'be52572c6d55f677ba76869d3c63805c0d4891a3', 'versionType': 'git'}, {'status': 'affected', 'version': '69894e5b4c5e28cda5f32af33d4a92b7a4b93b0e', 'lessThan': 'c8b6f36f766991e3ebebec6596daee4b04dcbc49', 'versionType': 'git'}, {'status': 'affected', 'version': 'f85623af16b83615e5f64a9b19ae1d584805cb07', 'versionType': 'git'}, {'status': 'affected', 'version': '5.10.248', 'lessThan': '5.10.261', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.198', 'lessThan': '5.15.212', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.1.160', 'lessThan': '6.1.178', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.6.120', 'lessThan': '6.6.145', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.12.63', 'lessThan': '6.12.97', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.18.2', 'lessThan': '6.18.40', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.17.13', 'lessThan': '6.18', 'versionType': 'semver'}], 'programFiles': ['net/netfilter/nf_conncount.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.19'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.19', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/nf_conncount.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '460c112e1d887b58b06b56e8e0230058906ff2c3', 'lessThan': '000ac6830b56499d6b65fd91486ce6689eb02be4', 'versionType': 'git'}, {'status': 'affected', 'version': '53bc0ac47f4f7621c991807bc90e01df49561ac8', 'lessThan': 'cbe2d14a7c5b1fc71821fbfee5c4963917411e92', 'versionType': 'git'}, {'status': 'affected', 'version': 'ca8b4d1d6304a84ce2016fa2fe9a114b9607b839', 'lessThan': '3793d24de224943e0a6016bbeffb6f5c4cea2e3d', 'versionType': 'git'}, {'status': 'affected', 'version': '8286c02fe9100330475331253fc590f047963f90', 'lessThan': 'abef7f817217fcb62c11821d6b895063eadb2828', 'versionType': 'git'}, {'status': 'affected', 'version': 'b29ddccf36946a90323486221f39e9f88cc01b8e', 'lessThan': 'ebfe8249ba79e4ff0f1e3aad8787b992ef27f026', 'versionType': 'git'}, {'status': 'affected', 'version': '77ea3d8ac3d3d59b5ac9ad639e4ba107c0f2ff1e', 'lessThan': '329f2626ee5cb8fafdf6b58b624311529c57cb45', 'versionType': 'git'}, {'status': 'affected', 'version': '69894e5b4c5e28cda5f32af33d4a92b7a4b93b0e', 'lessThan': 'be52572c6d55f677ba76869d3c63805c0d4891a3', 'versionType': 'git'}, {'status': 'affected', 'version': '69894e5b4c5e28cda5f32af33d4a92b7a4b93b0e', 'lessThan': 'c8b6f36f766991e3ebebec6596daee4b04dcbc49', 'versionType': 'git'}, {'status': 'affected', 'version': 'f85623af16b83615e5f64a9b19ae1d584805cb07', 'versionType': 'git'}, {'status': 'affected', 'version': '5.10.248', 'lessThan': '5.10.261', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.198', 'lessThan': '5.15.212', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.1.160', 'lessThan': '6.1.178', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.6.120', 'lessThan': '6.6.145', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.12.63', 'lessThan': '6.12.97', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.18.2', 'lessThan': '6.18.40', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.17.13', 'lessThan': '6.18', 'versionType': 'semver'}], 'programFiles': ['net/netfilter/nf_conncount.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.19'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.19', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/nf_conncount.c'], 'defaultStatus': 'affected'}] -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 15, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '460c112e1d887b58b06b56e8e0230058906ff2c3', 'lessThan': '000ac6830b56499d6b65fd91486ce6689eb02be4', 'versionType': 'git'}, {'status': 'affected', 'version': '53bc0ac47f4f7621c991807bc90e01df49561ac8', 'lessThan': 'cbe2d14a7c5b1fc71821fbfee5c4963917411e92', 'versionType': 'git'}, {'status': 'affected', 'version': 'ca8b4d1d6304a84ce2016fa2fe9a114b9607b839', 'lessThan': '3793d24de224943e0a6016bbeffb6f5c4cea2e3d', 'versionType': 'git'}, {'status': 'affected', 'version': '8286c02fe9100330475331253fc590f047963f90', 'lessThan': 'abef7f817217fcb62c11821d6b895063eadb2828', 'versionType': 'git'}, {'status': 'affected', 'version': 'b29ddccf36946a90323486221f39e9f88cc01b8e', 'lessThan': 'ebfe8249ba79e4ff0f1e3aad8787b992ef27f026', 'versionType': 'git'}, {'status': 'affected', 'version': '77ea3d8ac3d3d59b5ac9ad639e4ba107c0f2ff1e', 'lessThan': '329f2626ee5cb8fafdf6b58b624311529c57cb45', 'versionType': 'git'}, {'status': 'affected', 'version': '69894e5b4c5e28cda5f32af33d4a92b7a4b93b0e', 'lessThan': 'be52572c6d55f677ba76869d3c63805c0d4891a3', 'versionType': 'git'}, {'status': 'affected', 'version': '69894e5b4c5e28cda5f32af33d4a92b7a4b93b0e', 'lessThan': 'c8b6f36f766991e3ebebec6596daee4b04dcbc49', 'versionType': 'git'}, {'status': 'affected', 'version': 'f85623af16b83615e5f64a9b19ae1d584805cb07', 'versionType': 'git'}, {'status': 'affected', 'version': '5.10.248', 'lessThan': '5.10.261', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.198', 'lessThan': '5.15.212', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.1.160', 'lessThan': '6.1.178', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.6.120', 'lessThan': '6.6.145', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.12.63', 'lessThan': '6.12.97', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.18.2', 'lessThan': '6.18.40', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.17.13', 'lessThan': '6.18', 'versionType': 'semver'}], 'programFiles': ['net/netfilter/nf_conncount.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.19'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.19', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/nf_conncount.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conncount: prevent connlimit drops for early confirmed ct Commit 69894e5b4c5e ("netfilter: nft_connlimit: update the count if add was skipped") introduced a regression where packets for valid connections are dropped when using connlimit for soft-limiting scenarios. The issue occurs when a new connection reuses a socket currently in the TIME_WAIT state. In this scenario, the connection tracking entry is evaluated as already confirmed. Previously, __nf_conncount_add() assumed that if a connection was confirmed and did not originate from the loopback interface, it should skip the addition and return -EEXIST. Skipping the addition triggers a garbage collection run that cleans up the TIME_WAIT connection. Consequently, the active connection count drops to 0, which xt_connlimit mishandles, leading to the false rejection of the perfectly valid new connection. Fix this by replacing the interface check with protocol-agnostic state checks. We now skip the tree insertion and preserve the lockless garbage collection optimization only if the connection is IPS_ASSURED. This allows early-confirmed setup packets (such as reused TIME_WAIT sockets or locally generated SYN-ACKs) to be properly evaluated and counted without falsely dropping. The goto check_connections path is maintained to ensure these setup packets are deduplicated correctly. This has been tested with slowhttptest and HTTP server configured locally to ensure we are not breaking soft-limiting scenarios for local or external connections. In addition, it was tested with a OVS zone limit too. Added Reference https://git.kernel.org/stable/c/000ac6830b56499d6b65fd91486ce6689eb02be4 Added Reference https://git.kernel.org/stable/c/329f2626ee5cb8fafdf6b58b624311529c57cb45 Added Reference https://git.kernel.org/stable/c/3793d24de224943e0a6016bbeffb6f5c4cea2e3d Added Reference https://git.kernel.org/stable/c/abef7f817217fcb62c11821d6b895063eadb2828 Added Reference https://git.kernel.org/stable/c/be52572c6d55f677ba76869d3c63805c0d4891a3 Added Reference https://git.kernel.org/stable/c/c8b6f36f766991e3ebebec6596daee4b04dcbc49 Added Reference https://git.kernel.org/stable/c/cbe2d14a7c5b1fc71821fbfee5c4963917411e92 Added Reference https://git.kernel.org/stable/c/ebfe8249ba79e4ff0f1e3aad8787b992ef27f026
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.