High severity · published Oct 2, 2026
CVE-2026-104437
Zebra before 4.4.0 Consensus Split via SIGHASH_SINGLE Missing-Output Handling
7.4
CVSS
0.2%
EPSS
No
On KEV
Description
Zebra before 4.4.0 contains a consensus divergence vulnerability in V5 transparent signature verification, computing a ZIP-244 digest for SIGHASH_SINGLE inputs lacking corresponding outputs instead of failing. Attackers can craft V5 transactions with fewer outputs than inputs that Zebra accepts and templates via getblocktemplate, producing blocks zcashd rejects.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 16% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZE
zebra · ZcashFoundation
before 4.4.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-104437
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-104437
vendor-advisory
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-cwfq-rfcr-8hmp
third-party-advisory
https://www.vulncheck.com/advisories/zebra-before-4.4.0-consensus-split-via-sighash-single-missing-output-handling
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