vxlan: reject dynamic fdb entries that reference a nexthop id
In the Linux kernel, the following vulnerability has been resolved: vxlan: reject dynamic fdb entries that reference a nexthop id The commit cited in the Fixes tag allowed VXLAN FDB entries to point to FDB nexthops so that overlay traffic could be load balanced across multiple VTEPs. Such entries can only be configured from user space, cannot be learned and cannot roam. They only make sense with a user space control plane such as E-VPN where data plane learning is disabled. Despite that, the VXLAN driver does not currently prevent such entries from being configured with the "dynamic" flag. The per-nexthop FDB list is only protected by the per-device hash lock, which is not sufficient when two VXLAN devices point to the same FDB nexthop and therefore share the list. Aging runs in softirq context without RTNL, so an entry deleted by one device can race with an addition or deletion from the other, leading to list corruption: list_del corruption. next->prev should be ffff8881069d9548, but was dead000000000122. (next=ffff8881069d9448) WARNING: CPU: 0 PID: 90 at lib/list_debug.c:65 __list_del_entry_valid_or_report+0x1aa/0x210 ... vxlan_fdb_destroy+0x5b8/0xad0 vxlan_cleanup+0x328/0x450 call_timer_fn+0x2a/0x1c0 run_timer_softirq+0x18c/0x210 BUG: KASAN: slab-use-after-free in vxlan_fdb_destroy Fix this by rejecting the bogus configuration of dynamic FDB entries that point to FDB nexthops, both when created and when an existing entry is updated. As such, the per-nexthop FDB list is onl
CVE-2026-98023
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-2026-98023
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": "1274e1cc42264d4e629841e4f182795cb0becfd2",
"lessThan": "00c7f4b8144e535ffb931ad45942a1bd1315b882",
"versionType": "git"
},
{
"status": "affected",
"version": "1274e1cc42264d4e629841e4f182795cb0becfd2",
"lessThan": "55a33882808f1402052d53a08ead59aff8af18a1",
"versionType": "git"
},
{
"status": "affected",
"version": "1274e1cc42264d4e629841e4f182795cb0becfd2",
"lessThan": "c8f29af91e0830fdabc9aa1eb1a0f898ce1bc603",
"versionType": "git"
},
{
"status": "affected",
"version": "1274e1cc42264d4e629841e4f182795cb0becfd2",
"lessThan": "b2a8e165ddb6cd72176890b2954c52b0f6dbce1a",
"versionType": "git"
},
{
"status": "affected",
"version": "1274e1cc42264d4e629841e4f182795cb0becfd2",
"lessThan": "28f86eec851b7406a4bc6143f82aeba2882d9842",
"versionType": "git"
},
{
"status": "affected",
"version": "1274e1cc42264d4e629841e4f182795cb0becfd2",
"lessThan": "53359916ceb649b7e6947c8c2f669368a41c1354",
"versionType": "git"
},
{
"status": "affected",
"version": "1274e1cc42264d4e629841e4f182795cb0becfd2",
"lessThan": "3fa64d86fc64eda104e3e97721a12a42a2fd2073",
"versionType": "git"
},
{
"status": "affected",
"version": "1274e1cc42264d4e629841e4f182795cb0becfd2",
"lessThan": "98fc57d167446b95b4e719815fe79edef93f8e7a",
"versionType": "git"
}
],
"programFiles": [
"drivers/net/vxlan/vxlan_core.c",
"tools/testing/selftests/net/fib_nexthops.sh"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.271",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.222",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/net/vxlan/vxlan_core.c",
"tools/testing/selftests/net/fib_nexthops.sh"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98023
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #38148 · Revision 1
- Added to Heist Feed
- Publisher date