November 14, 2026

CVE Watchtower

CVE-2026-123556ZcashFoundation zebra Protection Mechanism Failure

NVD

Vulnerability Summary

ZcashFoundation Zebra from 4.5.0 before 7.0.0 contains a protection mechanism failure that bans honest peers by scoring mempool lock-time rejections at the ban threshold. Attackers can broadcast transactions locked until the current height right after each block, causing lagging nodes to ban honest relaying peers for 24 hours or until restart.
Severity Level
MEDIUM(6.9)
Published Date
Nov 8, 2026
Last Modified
Nov 12, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.30%Probability
Root Weakness (CWE)
CWE-693: Protection Mechanism Failure ↗
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks.
CVSS v4.0 Base Metrics — Score 6.9 (MEDIUM)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Attack VectorNetwork
Attack ComplexityLow
Attack RequirementsNone
Privileges RequiredNone
User InteractionNone
Confidentiality (Vulnerable System)None
Integrity (Vulnerable System)None
Availability (Vulnerable System)Low
Confidentiality (Subsequent System)None
Integrity (Subsequent System)None
Availability (Subsequent System)None
Show CVSS v3.x metrics (score 5.3)
CVSS v3.1 Base Metrics — Score 5.3 (MEDIUM)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityLow

Affected & Patched Versions

Affected Versions
  • ZcashFoundation zebra >= 4.5.0 and < 7.0.0
Patched Versions
  • ZcashFoundation zebra 7.0.0

What to do

Fix it during your normal patch cycle. No exploitation is confirmed yet.

  1. Check whether you run ZcashFoundation zebra and which version.
  2. Update to a patched version listed above, then confirm the new version.

Timeline

  • Nov 8, 2026Published
  • Nov 12, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Data last checked: Nov 14, 2026 02:13 UTC