CVE-2026-98122

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: mdb: Fix use-after-free in vxlan_mdb_remote_src_del()

vxlan_mdb_is_valid_source(), which validates MDBE_ATTR_SOURCE and every MDBE_ATTR_SRC_LIST member, accepts the all-zeros address.

A source list is only accepted on a (*, G) entry, whose source is the all-zeros address, and for each member of the list an (S, G) entry is derived from it by substituting the source. Entries are keyed by a plain memcmp() of struct vxlan_mdb_entry_key, so if MDBE_ATTR_SOURCE is present and holds the all-zeros address and the source list holds it as well, the derived (S, G) key is byte-identical to the (*, G) key and resolves to the same entry. Omitting MDBE_ATTR_SOURCE is not equivalent, as the key is then left with a zero address family.

vxlan_mdb_remote_src_del() removes the forwarding entry of a source before freeing the source entry:

vxlan_mdb_remote_src_fwd_del(vxlan, group, remote, &ent->addr); vxlan_mdb_remote_src_entry_del(ent);

With the keys aliased, the first call deletes the remote of the entry that owns 'ent' instead of a separate (S, G) entry, and frees 'ent'. The second call then runs on the freed entry, and its hlist_del() reads ->pprev and ->next out of it and writes through them.

Adding the (*, G) entry with NLM_F_REPLACE and no source list marks the all-zeros source for deletion and reaches this from the sweep at the end of vxlan_mdb_remote_srcs_replace().

BUG: KASAN: slab-use-after-free in __vxlan_mdb_add+0x1cd/0xd70 Read of size 8 at addr ffff888102852500 by task poc/84 __vxlan_mdb_add+0x1cd/0xd70 vxlan_mdb_add+0xc0/0x140 rtnl_mdb_add+0x157/0x2a0 rtnetlink_rcv_msg+0x207/0x5a0 Allocated by task 84: __kmalloc_cache_noprof+0x153/0x360 vxlan_mdb_remote_srcs_add+0x2eb/0x440 __vxlan_mdb_add+0x803/0xd70 Freed by task 84: kfree+0x14c/0x3b0 vxlan_mdb_remote_del+0x129/0x1a0 __vxlan_mdb_del+0x4f/0xe0 vxlan_mdb_remote_src_fwd_del.isra.0+0x162/0x1b0 __vxlan_mdb_add+0x1c5/0xd70

The MDB operations are netns-scoped, so an unprivileged user can perform them in a new user and network namespace.

Reject the all-zeros address in vxlan_mdb_is_valid_source(), which covers both call sites. A (*, G) entry is expressed by omitting the source, so nothing legitimate is refused.

Discovered by XBOW, triaged by Baul Lee

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: mdb: Fix use-after-free in vxlan_mdb_remote_src_del() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4aa61c88b4e292e10abdfd791334b8272108d68a
generic

vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/71203a41d6fa2fa0ea2f3a7541987958bd3694fd
generic

vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/74e2a56c82209b0335b53e25f19f9b0590e2483d
generic

vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e12c903fd13c6261b98ca18d8f70ac26e739e2f8

Vendor Advisories for CVE-2026-98122(2)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
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 46× in last 7d / 65× 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. 2026-10-05 03:01 UTCEG score recompute
  2. 2026-10-05 03:01 UTCVendor advisory
  3. 2026-10-05 03:01 UTCGHSA enrichment
  4. 2026-10-04 23:23 UTCEPSS rescore
  5. 2026-10-04 13:47 UTCVendor advisory
  6. 2026-10-04 13:47 UTCGHSA enrichment
  7. 2026-10-04 00:36 UTCEG score recompute
  8. 2026-10-04 00:36 UTCVendor advisory
  9. 2026-10-04 00:36 UTCGHSA enrichment
  10. 2026-10-03 14:26 UTCEPSS rescore
  11. 2026-10-03 11:27 UTCEG score recompute
  12. 2026-10-03 11:27 UTCVendor advisory
  13. 2026-10-03 11:27 UTCGHSA enrichment
  14. 2026-10-03 11:12 UTCEG score recompute
  15. 2026-10-03 11:12 UTCVendor advisory
  16. 2026-10-03 11:11 UTCGHSA enrichment
  17. 2026-10-03 08:33 UTCVendor advisory
  18. 2026-10-03 08:33 UTCGHSA enrichment
  19. 2026-10-02 19:21 UTCEG score recompute
  20. 2026-10-02 19:21 UTCVendor advisory
  21. 2026-10-02 19:21 UTCGHSA enrichment
  22. 2026-10-02 17:57 UTCEPSS rescore
  23. 2026-10-02 06:11 UTCEG score recompute
  24. 2026-10-02 06:11 UTCVendor advisory
  25. 2026-10-02 06:11 UTCGHSA enrichment
Show 40 more
  1. 2026-10-01 19:51 UTCEPSS rescore
  2. 2026-10-01 17:01 UTCVendor advisory
  3. 2026-10-01 17:01 UTCGHSA enrichment
  4. 2026-10-01 03:43 UTCEG score recompute
  5. 2026-10-01 03:43 UTCVendor advisory
  6. 2026-10-01 03:43 UTCGHSA enrichment
  7. 2026-09-30 15:04 UTCEPSS rescore
  8. 2026-09-30 14:33 UTCVendor advisory
  9. 2026-09-30 14:33 UTCGHSA enrichment
  10. 2026-09-30 14:06 UTCVendor advisory
  11. 2026-09-30 14:06 UTCGHSA enrichment
  12. 2026-09-30 00:55 UTCEG score recompute
  13. 2026-09-30 00:55 UTCVendor advisory
  14. 2026-09-30 00:55 UTCGHSA enrichment
  15. 2026-09-29 11:45 UTCVendor advisory
  16. 2026-09-29 11:45 UTCGHSA enrichment
  17. 2026-09-28 22:32 UTCEG score recompute
  18. 2026-09-28 22:32 UTCVendor advisory
  19. 2026-09-28 22:32 UTCGHSA enrichment
  20. 2026-09-28 13:52 UTCEPSS rescore
  21. 2026-09-28 13:52 UTCEPSS rescore
  22. 2026-09-28 09:22 UTCVendor advisory
  23. 2026-09-28 09:22 UTCGHSA enrichment
  24. 2026-09-27 20:12 UTCEG score recompute
  25. 2026-09-27 20:12 UTCGHSA enrichment
  26. 2026-09-27 13:49 UTCEPSS rescore
  27. 2026-09-27 07:02 UTCGHSA enrichment
  28. 2026-09-26 17:51 UTCEG score recompute
  29. 2026-09-26 17:51 UTCGHSA enrichment
  30. 2026-09-26 15:59 UTCEPSS rescore
  31. 2026-09-26 04:38 UTCEG score recompute
  32. 2026-09-26 04:37 UTCGHSA enrichment
  33. 2026-09-25 15:23 UTCEG score recompute
  34. 2026-09-25 15:23 UTCGHSA enrichment
  35. 2026-09-25 14:51 UTCEG score recompute▲ 7.80
  36. 2026-09-25 14:51 UTCGHSA enrichment
  37. 2026-09-25 14:49 UTCMITRE cvelistV5CVSS v3 → 7.8 · severity → HIGH
  38. 2026-09-25 11:30 UTCNVD update
  39. 2026-09-25 10:48 UTCEG score recompute
  40. 2026-09-25 10:46 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-98122?
CVE-2026-98122 is a high vulnerability published on September 25, 2026. In the Linux kernel, the following vulnerability has been resolved: vxlan: mdb: Fix use-after-free in vxlanmdbremotesrcdel() vxlanmdbisvalidsource(), which validates MDBEATTRSOURCE and every MDBEATTRSRC_LIST member, accepts the all-zeros address. A source list is only accepted on a (*, G) entry,…
When was CVE-2026-98122 disclosed?
CVE-2026-98122 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-2026-98122 actively exploited?
CVE-2026-98122 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-2026-98122?
CVE-2026-98122 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-2026-98122?
No fix for CVE-2026-98122 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-2026-98122 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-2026-98122

Explore →

Is Your Infrastructure Affected by CVE-2026-98122?

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

Book a Demo →Browse All CVEs