Zebra before 6.4.0 contains an improper integrity validation vulnerability in the inbound gossip download path that allows unauthenticated peers to force dropping of new blocks without penalty. Attackers can serve a real block with a coinbase scriptSig rewritten to height 1, which keeps the ZIP-244 block hash, triggering a behind-tip drop before consensus validation and delaying tip discovery for mining backends.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
Low
Partial disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Zfnd Zebra
cpe:2.3:a:zfnd:zebra:*:*:*:*:*:*:*:*
|
— |
6.4.0
|
References 2
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4f6v-mj46-gxg3
GitHub Security Advisory (GHSA-4f6v-mj46-gxg3)
https://www.vulncheck.com/advisories/zebra-before-6.4.0-gossiped-block-drop-via…
VulnCheck Advisory: Zebra before 6.4.0 Gossiped Block Drop via Forged Coinbase scriptSig Height