vxlan: use one headroom snapshot for neighbour replies
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.
CVE-2026-98568
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-98568
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
"lessThan": "45a67662bf8ce3aa5643accf98d328dfbb47eaf6",
"versionType": "git"
},
{
"status": "affected",
"version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
"lessThan": "315d42ca39f69846662961c25dcf2bb07c350d14",
"versionType": "git"
},
{
"status": "affected",
"version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
"lessThan": "a3c5eb6e382dd426a5e7eb08608897ed57167ff7",
"versionType": "git"
},
{
"status": "affected",
"version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
"lessThan": "ff022fd9d0f0282c575e11778b96bd1b637503eb",
"versionType": "git"
},
{
"status": "affected",
"version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
"lessThan": "481506a756dcd828ef42391cb08f38d8d96d38fc",
"versionType": "git"
},
{
"status": "affected",
"version": "d8be18c52dbc94989f6d74637b731af39cd3d902",
"versionType": "git"
},
{
"status": "affected",
"version": "3927dace523706cc00f808520eaf2125dd7c07b5",
"versionType": "git"
},
{
"status": "affected",
"version": "3.12.18",
"lessThan": "3.13",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.13.10",
"lessThan": "3.14",
"versionType": "semver"
}
],
"programFiles": [
"drivers/net/vxlan/vxlan_core.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.14"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.14",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.112",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.55",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.9",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/net/vxlan/vxlan_core.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98568
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38589 · Revision 1
- Added to Heist Feed
- Publisher date