Linux Kernel up to 6.17.7 net to/from ah6_output memory corruption

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.6	$0-$5k	0.00

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.17.7. Affected by this vulnerability is the function ah6_output of the file to/from of the component net. Executing a manipulation can lead to memory corruption. The identification of this vulnerability is CVE-2025-40363. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.17.7. This vulnerability affects the function ah6_output of the file to/from of the component net. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix field-spanning memcpy warning in AH output Fix field-spanning memcpy warnings in ah6_output() and ah6_output_done() where extension headers are copied to/from IPv6 address fields, triggering fortify-string warnings about writes beyond the 16-byte address fields. memcpy: detected field-spanning write (size 40) of single field "&top_iph->saddr" at net/ipv6/ah6.c:439 (size 16) WARNING: CPU: 0 PID: 8838 at net/ipv6/ah6.c:439 ah6_output+0xe7e/0x14e0 net/ipv6/ah6.c:439 The warnings are false positives as the extension headers are intentionally placed after the IPv6 header in memory. Fix by properly copying addresses and extension headers separately, and introduce helper functions to avoid code duplication.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2025-40363 since 04/16/2025. The exploitation appears to be easy. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 02/21/2026).

The vulnerability scanner Nessus provides a plugin with the ID 282382 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1350)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.302, 5.10.247, 5.15.197, 6.1.159, 6.6.117, 6.12.58 or 6.17.8 eliminates this vulnerability. Applying the patch 2da805a61ef5272a2773775ce14c3650adb84248/9bf27de51bd6db5ff827780ec0eba55de230ba45/0bf756ae1e69fec5e6332c37830488315d6d771b/75b16b2755e12999ad850756ddfb88ad4bfc7186/f28dde240160f3c48a50d641d210ed6a3b9596ed/c14cf41094136691c92ef756872570645d61f4a1/b056f971bd72b373b7ae2025a8f3bd18f69653d3/2327a3d6f65ce2fe2634546dde4a25ef52296fec 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 (282382) and CERT Bund (WID-SEC-2025-2868). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.4.301
• 5.10.246
• 5.15.196
• 6.1.158
• 6.6.116
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.12.53
• 6.12.54
• 6.12.55
• 6.12.56
• 6.12.57
• 6.17.0
• 6.17.1
• 6.17.2
• 6.17.3
• 6.17.4
• 6.17.5
• 6.17.6
• 6.17.7

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
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CPE 2.2info

• 🔒
• 🔒
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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.0
VulDB Meta Temp Score: 7.6

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

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
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Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 282382
Nessus Name: Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1350)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.4.302/5.10.247/5.15.197/6.1.159/6.6.117/6.12.58/6.17.8
Patch: 2da805a61ef5272a2773775ce14c3650adb84248/9bf27de51bd6db5ff827780ec0eba55de230ba45/0bf756ae1e69fec5e6332c37830488315d6d771b/75b16b2755e12999ad850756ddfb88ad4bfc7186/f28dde240160f3c48a50d641d210ed6a3b9596ed/c14cf41094136691c92ef756872570645d61f4a1/b056f971bd72b373b7ae2025a8f3bd18f69653d3/2327a3d6f65ce2fe2634546dde4a25ef52296fec

Timelineinfo

04/16/2025 CVE reserved
12/16/2025 +244 days Advisory disclosed
12/16/2025 +0 days VulDB entry created
02/21/2026 +67 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-40363 (🔒)
GCVE (CVE): GCVE-0-2025-40363
GCVE (VulDB): GCVE-100-336754
CERT Bund: WID-SEC-2025-2868 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 12/16/2025 16:00
Updated: 02/21/2026 04:30
Changes: 12/16/2025 16:00 (60), 01/08/2026 20:30 (2), 01/14/2026 02:59 (7), 01/19/2026 16:50 (1), 02/02/2026 13:18 (1), 02/21/2026 04:30 (1)
Complete: 🔍
Cache ID: 216::103

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Discussion

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