Not yet scoredPublished Dec 16, 2025

CVE-2025-40363net: ipv6: fix field-spanning memcpy warning in AH output

Updated under an hour ago (Oct 27, 2026, 3:23 PM ET)

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Exploited in the last 30 days

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.

CVSS: Not yet scored
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Deferred
Record last updated: Jun 16, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 2da805a61ef5272a2773775ce14c3650adb84248; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 9bf27de51bd6db5ff827780ec0eba55de230ba45; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 builds before 0bf756ae1e69fec5e6332c37830488315d6d771b; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 75b16b2755e12999ad850756ddfb88ad4bfc7186; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before f28dde240160f3c48a50d641d210ed6a3b9596ed; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before c14cf41094136691c92ef756872570645d61f4a1; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before b056f971bd72b373b7ae2025a8f3bd18f69653d3; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 2327a3d6f65ce2fe2634546dde4a25ef52296fec	CNA record

References

References

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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.