VDB-362045 · CVE-2026-43284 · EUVD-2026-28535

Linux Kernel up to 6.6.137/6.12.86/6.18.27/7.0.4 xfrm skb_splice_from_iter write-what-where condition

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7.2	$0-$5k	0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.6.137/6.12.86/6.18.27/7.0.4. It has been classified as critical. This affects the function skb_splice_from_iter of the component xfrm. The manipulation leads to an unknown weakness. This vulnerability is referenced as CVE-2026-43284. Furthermore, an exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.6.137/6.12.86/6.18.27/7.0.4. This issue affects the function skb_splice_from_iter of the component xfrm. Using CWE to declare the problem leads to CWE-123. Any condition where the attacker has the ability to write an arbitrary value to an arbitrary location, often as the result of a buffer overflow. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: xfrm: esp: avoid in-place decrypt on shared skb frags MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(), so later paths that may modify packet data can first make a private copy. The IPv4/IPv6 datagram append paths did not set this flag when splicing pages into UDP skbs. That leaves an ESP-in-UDP packet made from shared pipe pages looking like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW fast path for uncloned skbs without a frag_list and decrypts in place over data that is not owned privately by the skb. Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching TCP. Also make ESP input fall back to skb_cow_data() when the flag is present, so ESP does not decrypt externally backed frags in place. Private nonlinear skb frags still use the existing fast path. This intentionally does not change ESP output. In esp_output_head(), the path that appends the ESP trailer to existing skb tailroom without calling skb_cow_data() is not reachable for nonlinear skbs: skb_tailroom() returns zero when skb->data_len is nonzero, while ESP tailen is positive. Thus ESP output will either use the separate destination-frag path or fall back to skb_cow_data().

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-43284 since 05/01/2026. Technical details as well as a public exploit are known.

The exploit is available at exploit-db.com. It is declared as proof-of-concept. The vulnerability scanner Nessus provides a plugin with the ID 313239 (Linux Distros Unpatched Vulnerability : CVE-2026-43284), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.138, 6.12.87, 6.18.28 or 7.0.5 eliminates this vulnerability. Applying the patch 50ed1e7873100f77abad20fd31c51029bc49cd03/b54edf1e9a3fd3491bdcb82a21f8d21315271e0d/71a1d9d985d26716f74d21f18ee8cac821b06e97/52646cbd00e765a6db9c3afe9535f26218276034 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 Exploit-DB (52585), Tenable (313239), EUVD (EUVD-2026-28535) and CERT Bund (WID-SEC-2026-1430). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

Debian Linux
Google Cloud Platform
Amazon Linux 2
Red Hat Enterprise Linux
Fedora Linux
Mitel MiCollab
Ubuntu Linux
SUSE Linux
Oracle Linux
QNAP NAS
SUSE openSUSE
RESF Rocky Linux
Microsoft Azure Linux
Open Source Linux Kernel
Red Hat OpenShift
Red Hat OpenStack
Nutanix Files
Nutanix Kubernetes Engine
Mitel OpenScape
Mitel Performance Analytics
Mitel SIP Phone
IBM QRadar SIEM
Moxa MXsecurity

Productinfo

Type

Operating System

Vendor

Linux

Name

Kernel

Version

License

open-source

Website

Vendor: https://www.kernel.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.4
VulDB Meta Temp Score: 7.2

VulDB Base Score: 5.5
VulDB Temp Score: 5.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.8
CNA Vector (Linux): 🔒

ADP CISA Base Score: 7.8
ADP CISA Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Write-what-where condition
CWE: CWE-123 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒