CVE-2026-104436

Description

Zebra before 4.5.0 contains an uncontrolled resource consumption vulnerability that allows remote P2P peers to exhaust blocking-pool threads by sending oversized block locator vectors. Attackers can send getblocks or getheaders messages with up to 65,535 locator hashes, triggering per-hash chain lookups that degrade block validation, RPC, and mempool performance.

CVSS Vector

References

• https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-443g-gwgp-49x4
• https://www.vulncheck.com/advisories/zebra-before-4.5.0-cpu-amplification-via-uncapped-getblocks-getheaders-locator-length