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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 0bf756ae1e69fec5e6332c37830488315d6d771b, 2327a3d6f65ce2fe2634546dde4a25ef52296fec, 2da805a61ef5272a2773775ce14c3650adb84248.

Low priority for now. Upgrade to Linux Linux 0bf756ae1e69fec5e6332c37830488315d6d771b, 2327a3d6f65ce2fe2634546dde4a25ef52296fec, 2da805a61ef5272a2773775ce14c3650adb84248 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Dec 16, 2025
Updated
Oct 14, 2026
EPSS
0.2% · 11th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2da805a61ef5272a2773775ce14c3650adb84248affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 9bf27de51bd6db5ff827780ec0eba55de230ba45affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 0bf756ae1e69fec5e6332c37830488315d6d771baffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 75b16b2755e12999ad850756ddfb88ad4bfc7186affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before f28dde240160f3c48a50d641d210ed6a3b9596edaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before c14cf41094136691c92ef756872570645d61f4a1affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before b056f971bd72b373b7ae2025a8f3bd18f69653d3affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2327a3d6f65ce2fe2634546dde4a25ef52296fecaffected · git
    • before 2.6.12not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.159-16.1.159-1
Debian:13linuxbefore 6.12.63-16.12.63-1
Debian:14linuxbefore 6.17.8-16.17.8-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-40360Dec 16, 2025 · drm/sysfb: Do not dereference NULL pointer in plane reset
    0Monitor
  • ← EarlierCVE-2025-40362Dec 16, 2025 · ceph: fix multifs mds auth caps issue
    35Monitor
  • Later →CVE-2025-68167Dec 16, 2025 · gpiolib: fix invalid pointer access in debugfs
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0bf756ae1e69fec5e6332c37830488315d6d771bVendor (CNA)
Linux Linux2327a3d6f65ce2fe2634546dde4a25ef52296fecVendor (CNA)
Linux Linux2da805a61ef5272a2773775ce14c3650adb84248Vendor (CNA)
Linux Linux75b16b2755e12999ad850756ddfb88ad4bfc7186Vendor (CNA)
Linux Linux9bf27de51bd6db5ff827780ec0eba55de230ba45Vendor (CNA)
Linux Linuxb056f971bd72b373b7ae2025a8f3bd18f69653d3Vendor (CNA)
Linux Linuxc14cf41094136691c92ef756872570645d61f4a1Vendor (CNA)
Linux Linuxf28dde240160f3c48a50d641d210ed6a3b9596edVendor (CNA)
debian:linux6.1.159-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records