CVE-2026-104436

Zebra before 4.5.0 CPU Amplification via Uncapped getblocks/getheaders Locator Length

State: Published
Severity: 6.3 Medium
Published: Oct 2, 2026
Updated: Oct 29, 2026
Reserved: Oct 2, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	6.3 Medium	CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N	VulnCheck
3.1	3.7 Low	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L	VulnCheck

Weaknesses

CWE-770 Allocation of Resources Without Limits or Throttling

Affected Products

Product	Versions
zebraZcashFoundation	before 4.5.0Affected 4.5.0Not affected
zebra-chainZcashFoundation	before 8.0.0Affected 8.0.0Not affected

References

GitHub Security Advisory (GHSA-443g-gwgp-49x4)vendor-advisory
VulnCheck Advisory: Zebra before 4.5.0 CPU Amplification via Uncapped getblocks/getheaders Locator Lengththird-party-advisory

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