CVE-2026-109363
Zebra 6.4.0 before 6.4.2 Denial of Service via Malformed v6 Transaction
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
ZcashFoundation Zebra 6.4.0 before 6.4.2 parses version 6 transactions carrying a pre-NU6.3 consensus branch ID, but the size computation during UnminedTx construction treats re-serialization of the Orchard bundle as infallible, so the resulting error trips an expect that aborts zebrad. Unauthenticated peers can send a single pre-handshake tx message to crash the node, and can repeat this after each restart.
| CWE | CWE-617 |
| Vendor | zcashfoundation |
| Product | zebra |
| Published | Oct 12, 2026 |
Stay Ahead of the Next One
Get instant alerts for zcashfoundation zebra
Be the first to know when new high vulnerabilities affecting zcashfoundation zebra are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
ZcashFoundation / zebra
6.4.0 < 6.4.2
References
github.com: https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-h5rr-8pqv-grp9 github.com: https://github.com/ZcashFoundation/zebra/commit/008abac5c99e872f283450d596d95e37851df49a vulncheck.com: https://www.vulncheck.com/advisories/zebra-6.4.0-before-6.4.2-denial-of-service-via-malformed-v6-transaction
Credits
conradoplg mpguerra