Answer in brief
CVE-2026-98023 records a High severity (CVSS 7.8) vulnerability in vxlan: reject dynamic fdb entries that reference a nexthop id. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1274e1cc42264d4e629841e4f182795cb0becfd2 <28f86eec851b7406a4bc6143f82aeba2882d9842 || >=1274e1cc42264d4e629841e4f182795cb0becfd2 <53359916ceb649b7e6947c8c2f669368a41c1354 || >=1274e1cc42264d4e629841e4f182795cb0becfd2 <3fa64d86fc64eda104e3e97721a12a42a2fd2073 || >=1274e1cc42264d4e629841e4f182795cb0becfd2 <98fc57d167446b95b4e719815fe79edef93f8e7a | 28f86eec851b7406a4bc6143f82aeba2882d9842, 53359916ceb649b7e6947c8c2f669368a41c1354, 3fa64d86fc64eda104e3e97721a12a42a2fd2073, 98fc57d167446b95b4e719815fe79edef93f8e7a |
| Linux/Linuxgeneric | 5.8 | Not reported |
Published upstream
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 25, 2026
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 only ever mutated under the RTNL lock. Add test cases to make sure that this does not regress in the future.
Quoted source text, attributed separately from HOL analysis.