CVE-2026-104427 Zebra before 6.1.0 Chain Stall via Stale parent_error_map Entry
Remote attackers can stall Zcash node synchronization by poisoning error maps with malleated blocks, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-104427?
CVE-2026-104427 is a high-severity denial of service vulnerability in ZcashFoundation zebra, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Zebra before 6.1.0 contains an incomplete cleanup vulnerability in the state write task that allows remote unauthenticated peers to stall node synchronization by poisoning parent_error_map. Attackers can deliver a coinbase-malleated block sharing a canonical block's hash before it propagates, causing the next canonical block to be rejected and stalling the node for roughly 2,000 blocks.
Weakness: CWE-459
Which versions are affected by CVE-2026-104427?
How do I fix CVE-2026-104427?
No fix has been published for CVE-2026-104427 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-104427 being exploited?
There is no known exploitation of CVE-2026-104427 in the wild and no public exploit code.
Sources
Also known as GHSA-3c42-fjf2-4p66, GHSA-8gxx-hc65-vv82.