CVE-2026-109364
Received Received - Intake

Protection Mechanism Failure in Zebra 2.3.0 Allows IP Ban Evasion

Publication date: 2026-10-12

Last updated on: 2026-10-12

Assigner: VulnCheck

Description
Zebra 2.3.0 before 6.4.0 contains a protection mechanism failure that allows unauthenticated peers to evade bans because bans and misbehavior scores are keyed on exact IP addresses. Attackers can reconnect from fresh IPv6 addresses in their /64 allocation or flush the 20,000-entry FIFO ban list to restore access for banned peers.

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Meta Information

Published
2026-10-12
Last Modified
2026-10-12
Generated
2026-10-12
AI Q&A
2026-10-12
EPSS Evaluated
N/A
NVD
CVE-2026-109364
EUVD
EUVD-2026-97666

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
ZcashFoundation zebra 2.3.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-693 The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.

Attack-Flow Graph

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Executive Summary

Zebra versions 2.3.0 through 6.3.0 have a flaw where IP-based bans fail to block attackers. Bans and misbehavior scores are tied to exact IP addresses, allowing attackers to bypass restrictions by reconnecting from new IPv6 addresses within their /64 allocation or by clearing the 20,000-entry ban list.

Detection Guidance

Monitor for repeated connections from new IPv6 addresses within the same /64 allocation or unusual ban list evictions. Check Zebra logs for unauthenticated peers bypassing IP-based restrictions. Use network monitoring tools to track connections from suspicious IPv6 ranges.

Impact Analysis

Attackers can repeatedly exploit the system without consequences, as each new address resets their misbehavior score. They can also evict existing bans by flooding the ban list, undermining peer protection and allowing malicious activity to persist.

Mitigation Strategies
  • Upgrade Zebra to version 6.4.0 or later to address the protection mechanism failure.
  • Implement firewall rules to block abusive IPv6 ranges or entire /64 allocations associated with malicious activity.
  • Review and adjust ban list eviction policies to prevent flooding attacks that clear old bans.

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