Linux Kernel up to 6.19.11 netfilter flow_action_entry_next privilege escalation

CVSS Meta Temp Score
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CTI Interest Score
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6.5$0-$5k0.00

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.19.11. Affected is the function flow_action_entry_next of the component netfilter. Such manipulation leads to an unknown weakness. This vulnerability is listed as CVE-2026-43329. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.19.11. Affected by this issue is the function flow_action_entry_next of the component netfilter. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: strictly check for maximum number of actions The maximum number of flowtable hardware offload actions in IPv6 is: * ethernet mangling (4 payload actions, 2 for each ethernet address) * SNAT (4 payload actions) * DNAT (4 payload actions) * Double VLAN (4 vlan actions, 2 for popping vlan, and 2 for pushing) for QinQ. * Redirect (1 action) Which makes 17, while the maximum is 16. But act_ct supports for tunnels actions too. Note that payload action operates at 32-bit word level, so mangling an IPv6 address takes 4 payload actions. Update flow_action_entry_next() calls to check for the maximum number of supported actions. While at it, rise the maximum number of actions per flow from 16 to 24 so this works fine with IPv6 setups.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-43329 since 05/01/2026. 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 07/27/2026).

The vulnerability scanner Nessus provides a plugin with the ID 316888 (CentOS 9 : kernel-5.14.0-708.el9), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22 or 6.19.12 eliminates this vulnerability. Applying the patch ead66c77303f760f6c30be96e2e20d5a77cef614/fe9018d3e94329f1951b00805a8640bc06f56ead/5382bb03e9c33b089d60788478b922a2dca284cc/57c78bd2e2dd08897acd35b2bf8bcef322e36f5e/504c9456699dcf4d15195ef34a0fa94a80bfc877/879959a7a2be814dd57568655eafa3d8f4d0309e/76522fcdbc3a02b568f5d957f7e66fc194abb893 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (316888) and CERT Bund (WID-SEC-2026-1454). Once again VulDB remains the best source for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Red Hat OpenShift
  • Microsoft Azure Linux
  • Open Source Linux Kernel
  • Proxmox Virtual Environment

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.6
VulDB Meta Temp Score: 6.5

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (Linux): 🔒

CVSSv2info

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

Exploitinginfo

Class: Privilege escalation
CWE: Unknown
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 316888
Nessus Name: CentOS 9 : kernel-5.14.0-708.el9

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.15.203/6.1.168/6.6.134/6.12.81/6.18.22/6.19.12
Patch: ead66c77303f760f6c30be96e2e20d5a77cef614/fe9018d3e94329f1951b00805a8640bc06f56ead/5382bb03e9c33b089d60788478b922a2dca284cc/57c78bd2e2dd08897acd35b2bf8bcef322e36f5e/504c9456699dcf4d15195ef34a0fa94a80bfc877/879959a7a2be814dd57568655eafa3d8f4d0309e/76522fcdbc3a02b568f5d957f7e66fc194abb893

Timelineinfo

05/01/2026 CVE reserved
05/08/2026 +7 days Advisory disclosed
05/08/2026 +0 days VulDB entry created
07/27/2026 +79 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43329 (🔒)
GCVE (CVE): GCVE-0-2026-43329
GCVE (VulDB): GCVE-100-362108
CERT Bund: WID-SEC-2026-1454 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 05/08/2026 16:26
Updated: 07/27/2026 01:07
Changes: 05/08/2026 16:26 (58), 05/18/2026 18:13 (11), 05/27/2026 12:45 (2), 06/18/2026 23:17 (7), 07/27/2026 01:07 (3)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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