CVE-2026-98023: Linux kernel · vxlan: reject dynamic fdb entries that reference a nexthop id
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that rejects dynamic FDB entries referencing FDB nexthops and enforces proper locking during list mutations. Users should apply the official kernel updates that include this patch to eliminate the race condition and memory corruption issues.
Description
A vulnerability in the Linux kernel's VXLAN driver allows dynamic forwarding database (FDB) entries referencing nexthop IDs to be configured with the dynamic flag, leading to potential list corruption and use-after-free errors. This occurs because the per-nexthop FDB list is not sufficiently protected against concurrent modifications when multiple VXLAN devices share the same FDB nexthop. The issue has been fixed by rejecting such dynamic FDB entries and ensuring list mutations occur under proper locking.
References
- ubuntu.com/security/CVE-2026-98023 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98023 (opens in a new tab)
- git.kernel.org/stable/c/28f86eec851b7406a4bc6143f82aeba2882d9842 (opens in a new tab)
- git.kernel.org/stable/c/3fa64d86fc64eda104e3e97721a12a42a2fd2073 (opens in a new tab)
- git.kernel.org/stable/c/98fc57d167446b95b4e719815fe79edef93f8e7a (opens in a new tab)
- git.kernel.org/stable/c/53359916ceb649b7e6947c8c2f669368a41c1354 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-98023 (opens in a new tab)
- git.kernel.org/stable/c/00c7f4b8144e535ffb931ad45942a1bd1315b882 (opens in a new tab)
- git.kernel.org/stable/c/55a33882808f1402052d53a08ead59aff8af18a1 (opens in a new tab)
- git.kernel.org/stable/c/b2a8e165ddb6cd72176890b2954c52b0f6dbce1a (opens in a new tab)
- git.kernel.org/stable/c/c8f29af91e0830fdabc9aa1eb1a0f898ce1bc603 (opens in a new tab)