CVE-2026-98023

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-25. A secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.8EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 7.8Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

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.

CVSS v3
7.8
EG Score
7.8HIGHhigh confidence
EG Risk
40
EG Risk 40/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.1%
EPSS %ILE
1st
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 25, 2026

Last Modified

October 3, 2026

Advisory Details (4)

Auto-updated Sep 25, 2026
No patch confirmed yet.
generic

vxlan: reject dynamic fdb entries that reference a nexthop id - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/98fc57d167446b95b4e719815fe79edef93f8e7a
generic

vxlan: reject dynamic fdb entries that reference a nexthop id - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3fa64d86fc64eda104e3e97721a12a42a2fd2073
generic

vxlan: reject dynamic fdb entries that reference a nexthop id - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/53359916ceb649b7e6947c8c2f669368a41c1354
generic

vxlan: reject dynamic fdb entries that reference a nexthop id - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/28f86eec851b7406a4bc6143f82aeba2882d9842

Vendor Advisories for CVE-2026-98023(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 7.2~rc7-1~exp1 (360 versions)
  • every version on: no fix on record
—
linux-6.126.12.100-1~deb12u1, 6.12.101-1~deb12u1, 6.12.107-1~deb12u1
  • every version up to 6.12.111-1~deb12u1: fixed in 6.12.111-1~deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.12.96-1 (35 versions)
  • every version up to 6.12.111-1: fixed in 6.12.111-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (180 versions)
  • every version up to 7.2.7-1: fixed in 7.2.7-1
—

Data Freshness Timeline

(refreshed 43× in last 7d / 61× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-04 23:23 UTCEPSS rescore
  2. 2026-10-04 22:29 UTCVendor advisory
  3. 2026-10-04 22:29 UTCGHSA enrichment
  4. 2026-10-04 10:51 UTCVendor advisory
  5. 2026-10-04 10:51 UTCGHSA enrichment
  6. 2026-10-03 23:11 UTCEG score recompute
  7. 2026-10-03 23:11 UTCVendor advisory
  8. 2026-10-03 23:11 UTCGHSA enrichment
  9. 2026-10-03 14:26 UTCEPSS rescore
  10. 2026-10-03 11:28 UTCVendor advisory
  11. 2026-10-03 11:28 UTCGHSA enrichment
  12. 2026-10-03 11:09 UTCVendor advisory
  13. 2026-10-03 11:09 UTCGHSA enrichment
  14. 2026-10-02 23:29 UTCEG score recompute
  15. 2026-10-02 23:29 UTCVendor advisory
  16. 2026-10-02 23:28 UTCGHSA enrichment
  17. 2026-10-02 17:57 UTCEPSS rescore
  18. 2026-10-02 11:47 UTCVendor advisory
  19. 2026-10-02 11:47 UTCGHSA enrichment
  20. 2026-10-02 00:03 UTCEG score recompute
  21. 2026-10-02 00:03 UTCVendor advisory
  22. 2026-10-02 00:03 UTCGHSA enrichment
  23. 2026-10-01 19:51 UTCEPSS rescore
  24. 2026-10-01 11:57 UTCVendor advisory
  25. 2026-10-01 11:57 UTCGHSA enrichment
Show 36 more
  1. 2026-10-01 00:15 UTCEG score recompute
  2. 2026-10-01 00:15 UTCVendor advisory
  3. 2026-10-01 00:15 UTCGHSA enrichment
  4. 2026-09-30 15:04 UTCEPSS rescore
  5. 2026-09-30 11:56 UTCVendor advisory
  6. 2026-09-30 11:56 UTCGHSA enrichment
  7. 2026-09-30 00:17 UTCEG score recompute
  8. 2026-09-30 00:17 UTCVendor advisory
  9. 2026-09-30 00:17 UTCGHSA enrichment
  10. 2026-09-29 12:38 UTCVendor advisory
  11. 2026-09-29 12:38 UTCGHSA enrichment
  12. 2026-09-29 00:59 UTCEG score recompute
  13. 2026-09-29 00:59 UTCVendor advisory
  14. 2026-09-29 00:59 UTCGHSA enrichment
  15. 2026-09-28 13:52 UTCEPSS rescore
  16. 2026-09-28 13:52 UTCEPSS rescore
  17. 2026-09-28 13:20 UTCVendor advisory
  18. 2026-09-28 13:20 UTCGHSA enrichment
  19. 2026-09-28 01:42 UTCGHSA enrichment
  20. 2026-09-27 14:00 UTCEG score recompute
  21. 2026-09-27 13:59 UTCGHSA enrichment
  22. 2026-09-27 13:49 UTCEPSS rescore
  23. 2026-09-27 02:19 UTCEG score recompute
  24. 2026-09-27 02:19 UTCGHSA enrichment
  25. 2026-09-26 15:59 UTCEPSS rescore
  26. 2026-09-26 14:40 UTCGHSA enrichment
  27. 2026-09-26 03:02 UTCEG score recompute
  28. 2026-09-26 03:02 UTCGHSA enrichment
  29. 2026-09-25 15:23 UTCEG score recompute
  30. 2026-09-25 15:23 UTCGHSA enrichment
  31. 2026-09-25 14:52 UTCEG score recompute▲ 7.80
  32. 2026-09-25 14:52 UTCGHSA enrichment
  33. 2026-09-25 14:49 UTCMITRE cvelistV5CVSS v3 → 7.8 · severity → HIGH
  34. 2026-09-25 11:30 UTCNVD update
  35. 2026-09-25 10:29 UTCEG score recompute
  36. 2026-09-25 10:27 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-98023?
CVE-2026-98023 is a high vulnerability published on September 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…
When was CVE-2026-98023 disclosed?
CVE-2026-98023 was first published on September 25, 2026, with the most recent update on October 3, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-98023 actively exploited?
CVE-2026-98023 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-98023?
CVE-2026-98023 has a CVSS base score of 7.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-98023?
No fix for CVE-2026-98023 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-98023 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-98023

Explore →

Is Your Infrastructure Affected by CVE-2026-98023?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs