CVE-2026-40881 Zebra: addr/addrv2 Deserialization Resource Exhaustion

What is CVE-2026-40881?

CVE-2026-40881 is a medium-severity denial of service vulnerability in ZcashFoundation zebra-network, published on 21 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.3.0 and zebra-network version 5.0.1, when deserializing addr or addrv2 messages, which contain vectors of addresses, Zebra would fully deserialize them up to a maximum length (over 233,000) that was derived from the 2 MiB message size limit. This is much larger than the actual limit of 1,000 messages from the specification. Zebra would eventually check that limit but, at that point, the memory for the larger vector was already allocated. An attacker could cause out-of-memory aborts in Zebra by sending multiple such messages over different connections. This vulnerability is fixed in zebrad version 4.3.0 and zebra-network version 5.0.1.

Weakness: CWE-770

Which versions are affected by CVE-2026-40881?

4 open source packages ship an affected version, including zebra-network and zebrad. It affects 2 products.

Products include Zfnd Zebra-Network, Zfnd Zebrad.

How do I fix CVE-2026-40881?

Upgrade zebra-network to 5.0.1 or later.

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-2026-40881 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40881 exists.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-xr93-pcq3-pxf8.