vxlan: use one headroom snapshot for neighbour replies
Summary
| CVE | CVE-2026-98568 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-18 16:17:09 UTC |
| Updated | 2026-10-30 13:21:16 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: vxlan: use one headroom snapshot for neighbour replies vxlan_na_create() samples LL_RESERVED_SPACE() to size the reply skb and then samples it again to reserve headroom. A concurrent vxlan_changelink() can update needed_headroom between the two reads, creating a TOCTOU race. The second value can exceed the allocation and make the Ethernet header write out of bounds. The race is reproducible on the unpatched kernel. It occurred when vxlan_na_create() generated a neighbour reply while vxlan_changelink() changed the link headroom. KASAN caught a four-byte write two bytes beyond a 704-byte skbuff_small_head allocation. Snapshot the headroom once and use that value for both allocation and reservation. |
Risk And Classification
EPSS: 0.002110000 probability, percentile 0.112960000 (date 2026-11-01)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa e3e24f4c434c56952412f875b834aa9daaa4fb15 git | Not specified |
| CNA | Linux | Linux | affected 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa 9ed5a548b42d46e6968a46b67ca8a8e49b12a5a1 git | Not specified |
| CNA | Linux | Linux | affected 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa fcaf456092dc86fd5b0b523ac27ec0d114066931 git | Not specified |
| CNA | Linux | Linux | affected 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa 45a67662bf8ce3aa5643accf98d328dfbb47eaf6 git | Not specified |
| CNA | Linux | Linux | affected 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa 315d42ca39f69846662961c25dcf2bb07c350d14 git | Not specified |
| CNA | Linux | Linux | affected 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa a3c5eb6e382dd426a5e7eb08608897ed57167ff7 git | Not specified |
| CNA | Linux | Linux | affected 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa ff022fd9d0f0282c575e11778b96bd1b637503eb git | Not specified |
| CNA | Linux | Linux | affected 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa 481506a756dcd828ef42391cb08f38d8d96d38fc git | Not specified |
| CNA | Linux | Linux | affected d8be18c52dbc94989f6d74637b731af39cd3d902 git | Not specified |
| CNA | Linux | Linux | affected 3927dace523706cc00f808520eaf2125dd7c07b5 git | Not specified |
| CNA | Linux | Linux | affected 3.12.18 3.13 semver | Not specified |
| CNA | Linux | Linux | affected 3.13.10 3.14 semver | Not specified |
| CNA | Linux | Linux | affected 3.14 | Not specified |
| CNA | Linux | Linux | unaffected 3.14 semver | Not specified |
| CNA | Linux | Linux | unaffected 5.10.273 5.10.* semver | Not specified |
| CNA | Linux | Linux | unaffected 5.15.224 5.15.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.191 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.158 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.112 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.55 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.9 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/e3e24f4c434c56952412f875b834aa9daaa4fb15 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/fcaf456092dc86fd5b0b523ac27ec0d114066931 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/a3c5eb6e382dd426a5e7eb08608897ed57167ff7 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/9ed5a548b42d46e6968a46b67ca8a8e49b12a5a1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/ff022fd9d0f0282c575e11778b96bd1b637503eb | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/315d42ca39f69846662961c25dcf2bb07c350d14 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/481506a756dcd828ef42391cb08f38d8d96d38fc | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/45a67662bf8ce3aa5643accf98d328dfbb47eaf6 | 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.