CVE-2026-104429 Zebra before 6.0.0-rc.0 Per-Peer Mempool Admission Bypass via P2P tx Messages
Remote peers can bypass mempool admission limits in Zebra, causing resource exhaustion and disrupting transaction relay for honest nodes.
- 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-2026-104429?
CVE-2026-104429 is a medium-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 (zebrad) 5.0.0 before 6.0.0-rc.0 does not apply its per-peer mempool admission cap to transactions received as direct P2P tx messages, because these are queued without the sending peer recorded as their source. A remote inbound peer can push many unique transactions to occupy a disproportionate share of mempool admission slots, crowding out honest peers' transaction relay.
Weakness: CWE-770
Which versions are affected by CVE-2026-104429?
How do I fix CVE-2026-104429?
No fix has been published for CVE-2026-104429 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-2026-104429 being exploited?
There is no known exploitation of CVE-2026-104429 in the wild and no public exploit code.
Sources
Also known as GHSA-36m2-g2jj-2c6x, GHSA-m9xx-8rcj-vmgp.