net: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone
Summary
| CVE | CVE-2026-80615 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-28 08:16:45 UTC |
| Updated | 2026-08-29 07:16:46 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: net: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone kmalloc_flex() in metadata_dst_alloc() sets __counted_by for the structure to the options_len, which is then initialized to zero. Later, we're initializing the structure by copying the tunnel info together with the options, and this triggers a warning for a potential memcpy overflow, since the compiler estimates that the options can't fit into the structure, even though the memory for them is actually allocated. memcpy: detected buffer overflow: 104 byte write of buffer size 96 WARNING: CPU: X PID: Y at lib/string_helpers.c:1036 __fortify_report skb_tunnel_info_unclone+0x179/0x190 geneve_xmit+0x7fe/0xe00 The issue is triggered when built with clang and source fortification. Fix that by doing the copy in two stages: first - the main data with the options_len, then the options. This way the correct length should be known at the time of the copy. It would be better if the options_len never changed after allocation, but the allocation code is a little separate from the initialization and it would be awkward and potentially dangerous to return a struct with options_len set to a non-zero value from the metadata_dst_alloc(). Another option would be to use ip_tunnel_info_opts_set(), but it is doing too many unnecessary operations for the use case here. |
Risk And Classification
Primary CVSS: v3.1 8.2 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
EPSS: 0.003510000 probability, percentile 0.279660000 (date 2026-08-31)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 8.2 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H |
| 3.1 | CNA | DECLARED | 8.2 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
LowIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 69050f8d6d075dc01af7a5f2f550a8067510366f 7ce31739fe88a558370135db95bbeec1e7ddfc29 git | Not specified |
| CNA | Linux | Linux | affected 69050f8d6d075dc01af7a5f2f550a8067510366f 4c6d43db2a4d2cef3921e885cf34798f790d34ea git | Not specified |
| CNA | Linux | Linux | affected 7.0 | Not specified |
| CNA | Linux | Linux | unaffected 7.0 semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.5 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/4c6d43db2a4d2cef3921e885cf34798f790d34ea | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/7ce31739fe88a558370135db95bbeec1e7ddfc29 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.