Resource exhaustion in Zcash - #VU137468
Published: July 14, 2026
Vulnerability identifier: #VU137468
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in zcashd block processing when handling repeated P2P block messages for a disk-persisted invalid pool-delta block. A remote attacker can replay the same specially crafted block message to cause a denial of service.
The initial block must have valid proof-of-work and an invalid aggregate value-pool delta, after which identical unauthenticated P2P replays can repeatedly append duplicate block bodies to disk because the block remains header-only and is not marked invalid.
Affected software
Zcash
Remediation
Install security update from vendor's website.
Zcash - update to 6.20.0