Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13 __nfulnl_send heap-based overflow

CVSS Meta Temp Score
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CTI Interest Score
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6.6$5k-$25k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13. The affected element is the function __nfulnl_send. Performing a manipulation results in heap-based overflow. This vulnerability was named CVE-2026-43085. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13. This affects the function __nfulnl_send. The manipulation with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_log: initialize nfgenmsg in NLMSG_DONE terminator When batching multiple NFLOG messages (inst->qlen > 1), __nfulnl_send() appends an NLMSG_DONE terminator with sizeof(struct nfgenmsg) payload via nlmsg_put(), but never initializes the nfgenmsg bytes. The nlmsg_put() helper only zeroes alignment padding after the payload, not the payload itself, so four bytes of stale kernel heap data are leaked to userspace in the NLMSG_DONE message body. Use nfnl_msg_put() to build the NLMSG_DONE terminator, which initializes the nfgenmsg payload via nfnl_fill_hdr(), consistent with how __build_packet_message() already constructs NFULNL_MSG_PACKET headers.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-43085 since 05/01/2026. The exploitability is told to be easy. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 06/23/2026).

The vulnerability scanner Nessus provides a plugin with the ID 322088 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1882)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.136, 6.12.83, 6.18.24 or 6.19.14 eliminates this vulnerability. Applying the patch 368c22aea490f6f50df831b4f9e3623787686c5b/d1399632ba255d2e02c757af5d9f5d9279ce168c/d552bcfca323d175664d7444989b04f55666978a/15d209bccf9273b4a8b4e579ba0e92d065b6ec8c/1f3083aec8836213da441270cdb1ab612dd82cf4 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 (322088) and CERT Bund (WID-SEC-2026-1385). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Microsoft Azure Linux

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.8
VulDB Meta Temp Score: 6.6

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
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: 322088
Nessus Name: Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1882)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.136/6.12.83/6.18.24/6.19.14
Patch: 368c22aea490f6f50df831b4f9e3623787686c5b/d1399632ba255d2e02c757af5d9f5d9279ce168c/d552bcfca323d175664d7444989b04f55666978a/15d209bccf9273b4a8b4e579ba0e92d065b6ec8c/1f3083aec8836213da441270cdb1ab612dd82cf4

Timelineinfo

05/01/2026 CVE reserved
05/06/2026 +5 days Advisory disclosed
05/06/2026 +0 days VulDB entry created
06/23/2026 +48 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43085 (🔒)
GCVE (CVE): GCVE-0-2026-43085
GCVE (VulDB): GCVE-100-361323
CERT Bund: WID-SEC-2026-1385 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 05/06/2026 12:50
Updated: 06/23/2026 20:12
Changes: 05/06/2026 12:50 (58), 05/07/2026 04:28 (7), 06/04/2026 11:08 (11), 06/08/2026 16:19 (1), 06/23/2026 20:12 (2)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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