What’s Vulnerable › Vulnerabilities

CVE-2026-104436: Zebra before 4.5.0 CPU Amplification via Uncapped getblocks/getheaders Locator Length

• Severity: low (CVSS 3.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-02 · updated 2026-10-29
• Weakness: CWE-770

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.

Affected products

• ZcashFoundation zebra-chain: before 8.0.0 — fixed in 8.0.0
• ZcashFoundation zebra: before 4.5.0 — fixed in 4.5.0

How to fix

Upgrade to a fixed version: ZcashFoundation zebra-chain 8.0.0; ZcashFoundation zebra 4.5.0. Check the vendor advisory for mitigations.

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

Get alerted when CVE-2026-104436 or the next vulnerability affects your stack