CVE-2025-40363

Description

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.

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References

Other References

https://git.kernel.org/stable/c/0bf756ae1e69fec5e6332c37830488315d6d771b https://git.kernel.org/stable/c/2327a3d6f65ce2fe2634546dde4a25ef52296fec https://git.kernel.org/stable/c/2da805a61ef5272a2773775ce14c3650adb84248 https://git.kernel.org/stable/c/75b16b2755e12999ad850756ddfb88ad4bfc7186 https://git.kernel.org/stable/c/9bf27de51bd6db5ff827780ec0eba55de230ba45 https://git.kernel.org/stable/c/b056f971bd72b373b7ae2025a8f3bd18f69653d3 https://git.kernel.org/stable/c/c14cf41094136691c92ef756872570645d61f4a1 https://git.kernel.org/stable/c/f28dde240160f3c48a50d641d210ed6a3b9596ed

Frequently Asked Questions

What is CVE-2025-40363? +

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.

How do I check if I'm vulnerable to CVE-2025-40363? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2025-40363

Description

References

Other References

Frequently Asked Questions

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