CVE-2026-104436

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

Published Oct 2, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Zfnd zebra-chain
CPEs cpe:2.3:a:zfnd:zebra-chain:*:*:*:*:*:*:*:*
Vendors & Products Zfnd zebra-chain
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Zcashfoundation
Zcashfoundation zebra
Vendors & Products Zcashfoundation
Zcashfoundation zebra
Type Values Removed Values Added
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.
Title Zebra before 4.5.0 CPU Amplification via Uncapped getblocks/getheaders Locator Length
First Time appeared Zfnd
Zfnd zebra
Weaknesses CWE-770
CPEs cpe:2.3:a:zfnd:zebra:*:*:*:*:*:*:*:*
Vendors & Products Zfnd
Zfnd zebra
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'}

cvssV4_0

{'score': 6.3, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 29, 2026, 9:15 PM
Reserved
Oct 2, 2026, 12:50 AM
Status
Deferred
Published
Oct 2, 2026, 12:17 PM
Modified
Oct 29, 2026, 9:17 PM