Low severity · published Oct 2, 2026
CVE-2026-104436
Zebra before 4.5.0 CPU Amplification via Uncapped getblocks/getheaders Locator Length
3.7
CVSS
0.3%
EPSS
No
On KEV
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
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 20% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZE
zebra · ZcashFoundation
before 4.5.0; before 8.0.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-104436
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-104436
vendor-advisory
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-443g-gwgp-49x4
third-party-advisory
https://www.vulncheck.com/advisories/zebra-before-4.5.0-cpu-amplification-via-uncapped-getblocks-getheaders-locator-length
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