CVE-2026-43100

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-05-06. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

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

In the Linux kernel, the following vulnerability has been resolved:

bridge: guard local VLAN-0 FDB helpers against NULL vlan group

When CONFIG_BRIDGE_VLAN_FILTERING is not set, br_vlan_group() and nbp_vlan_group() return NULL (br_private.h stub definitions). The BR_BOOLOPT_FDB_LOCAL_VLAN_0 toggle code is compiled unconditionally and reaches br_fdb_delete_locals_per_vlan_port() and br_fdb_insert_locals_per_vlan_port(), where the NULL vlan group pointer is dereferenced via list_for_each_entry(v, &vg->vlan_list, vlist).

The observed crash is in the delete path, triggered when creating a bridge with IFLA_BR_MULTI_BOOLOPT containing BR_BOOLOPT_FDB_LOCAL_VLAN_0 via RTM_NEWLINK. The insert helper has the same bug pattern.

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] KASAN NOPTI KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7] RIP: 0010:br_fdb_delete_locals_per_vlan+0x2b9/0x310 Call Trace: br_fdb_toggle_local_vlan_0+0x452/0x4c0 br_toggle_fdb_local_vlan_0+0x31/0x80 net/bridge/br.c:276 br_boolopt_toggle net/bridge/br.c:313 br_boolopt_multi_toggle net/bridge/br.c:364 br_changelink net/bridge/br_netlink.c:1542 br_dev_newlink net/bridge/br_netlink.c:1575

Add NULL checks for the vlan group pointer in both helpers, returning early when there are no VLANs to iterate. This matches the existing pattern used by other bridge FDB functions such as br_fdb_add() and br_fdb_delete().

CVSS v3
5.5
EG Score
5.5(medium)
EPSS
2.2%
KEV
Not listed

Published

May 6, 2026

Last Modified

May 11, 2026

References (3)

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 32× 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. 2026-07-16 17:03 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 02:00 UTCEPSS rescore
  4. 2026-07-13 22:30 UTCEPSS rescore
  5. 2026-07-13 06:13 UTCEPSS rescore
  6. 2026-07-12 05:46 UTCEPSS rescore
  7. 2026-07-11 08:27 UTCEPSS rescore
  8. 2026-07-09 19:10 UTCEPSS rescore
  9. 2026-07-08 15:16 UTCEPSS rescore
  10. 2026-07-07 13:46 UTCEPSS rescore
  11. 2026-07-06 16:27 UTCEPSS rescore
  12. 2026-07-06 02:23 UTCEPSS rescore
  13. 2026-07-05 02:30 UTCEPSS rescore
  14. 2026-07-04 06:31 UTCEPSS rescore
  15. 2026-07-01 15:06 UTCEPSS rescore
  16. 2026-06-30 23:22 UTCEPSS rescore
  17. 2026-06-29 14:06 UTCEPSS rescore
  18. 2026-06-28 14:07 UTCEPSS rescore
  19. 2026-06-28 04:56 UTCEPSS rescore
  20. 2026-06-27 03:08 UTCEPSS rescore
  21. 2026-06-25 13:49 UTCEPSS rescore
  22. 2026-06-25 13:49 UTCEPSS rescore
  23. 2026-06-24 14:05 UTCEPSS rescore
  24. 2026-06-23 21:33 UTCEPSS rescore
  25. 2026-06-22 14:25 UTCEPSS rescore
Show 62 more
  1. 2026-06-22 14:25 UTCEPSS rescore
  2. 2026-06-21 14:56 UTCEPSS rescore
  3. 2026-06-21 14:56 UTCEPSS rescore
  4. 2026-06-21 01:59 UTCEPSS rescore
  5. 2026-06-19 19:25 UTCEPSS rescore
  6. 2026-06-18 17:52 UTCEPSS rescore
  7. 2026-06-18 17:52 UTCEPSS rescore
  8. 2026-06-17 17:53 UTCEPSS rescore
  9. 2026-06-16 17:52 UTCEPSS rescore
  10. 2026-06-15 17:49 UTCEPSS rescore
  11. 2026-06-14 07:44 UTCGHSA enrichment
  12. 2026-06-13 23:00 UTCEPSS rescore
  13. 2026-06-12 23:12 UTCEPSS rescore
  14. 2026-06-12 23:12 UTCEPSS rescore
  15. 2026-06-12 09:13 UTCGHSA enrichment
  16. 2026-06-11 14:00 UTCEPSS rescore
  17. 2026-06-11 09:24 UTCGHSA enrichment
  18. 2026-06-10 22:18 UTCEPSS rescore
  19. 2026-06-10 13:22 UTCEPSS rescore
  20. 2026-06-10 13:22 UTCEPSS rescore
  21. 2026-06-10 09:27 UTCGHSA enrichment
  22. 2026-06-09 09:39 UTCGHSA enrichment
  23. 2026-06-08 14:17 UTCEPSS rescore
  24. 2026-06-08 14:17 UTCEPSS rescore
  25. 2026-06-08 08:51 UTCGHSA enrichment
  26. 2026-06-07 15:25 UTCEPSS rescore
  27. 2026-06-07 15:25 UTCEPSS rescore
  28. 2026-06-07 09:02 UTCGHSA enrichment
  29. 2026-06-06 13:47 UTCEPSS rescore
  30. 2026-06-06 13:47 UTCEPSS rescore
  31. 2026-06-06 09:14 UTCGHSA enrichment
  32. 2026-06-05 22:47 UTCEPSS rescore
  33. 2026-06-05 09:26 UTCGHSA enrichment
  34. 2026-06-05 06:10 UTCEPSS rescore
  35. 2026-06-05 06:10 UTCEPSS rescore
  36. 2026-06-04 13:12 UTCEPSS rescore
  37. 2026-06-04 13:12 UTCEPSS rescore
  38. 2026-06-04 09:37 UTCGHSA enrichment
  39. 2026-06-03 09:48 UTCGHSA enrichment
  40. 2026-06-02 20:13 UTCEPSS rescore
  41. 2026-06-02 09:31 UTCGHSA enrichment
  42. 2026-06-01 13:52 UTCEPSS rescore
  43. 2026-06-01 13:52 UTCEPSS rescore
  44. 2026-06-01 09:42 UTCGHSA enrichment
  45. 2026-05-31 22:30 UTCEPSS rescore
  46. 2026-05-31 22:30 UTCEPSS rescore
  47. 2026-05-31 00:16 UTCEPSS rescore
  48. 2026-05-31 00:16 UTCEPSS rescore
  49. 2026-05-29 13:44 UTCEPSS rescore
  50. 2026-05-29 13:44 UTCEPSS rescore
  51. 2026-05-28 13:44 UTCEPSS rescore
  52. 2026-05-28 13:44 UTCEPSS rescore
  53. 2026-05-27 13:40 UTCEPSS rescore
  54. 2026-05-27 13:40 UTCEPSS rescore
  55. 2026-05-26 13:44 UTCEPSS rescore
  56. 2026-05-26 07:18 UTCEPSS rescore
  57. 2026-05-20 22:38 UTCEPSS rescore
  58. 2026-05-20 22:38 UTCEPSS rescore
  59. 2026-05-20 14:22 UTCEG score recompute
  60. 2026-05-20 14:21 UTCGHSA enrichment
  61. 2026-05-20 11:22 UTCEPSS rescore
  62. 2026-05-20 11:22 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-43100?
CVE-2026-43100 is a medium vulnerability published on May 6, 2026. In the Linux kernel, the following vulnerability has been resolved: bridge: guard local VLAN-0 FDB helpers against NULL vlan group When CONFIGBRIDGEVLANFILTERING is not set, brvlan_group() and nbpvlangroup() return NULL (br_private.h stub definitions). The BRBOOLOPTFDBLOCALVLAN_0 toggle code is…
When was CVE-2026-43100 disclosed?
CVE-2026-43100 was first published in the National Vulnerability Database on May 6, 2026, with the most recent update on May 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-43100 actively exploited?
CVE-2026-43100 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-43100?
CVE-2026-43100 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-43100?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43100, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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