High severity · published May 8, 2026
CVE-2026-44498
ZEBRA: Block Validator Undercounts Coinbase and P2SH Sigops
7.5
CVSS
0.3%
EPSS
No
On KEV
Description
ZEBRA is a Zcash node written entirely in Rust. Prior to version 4.4.0, Zebra's block validator undercounts transparent signature operations against the 20000-sigop block limit (MAX_BLOCK_SIGOPS), allowing it to accept blocks that zcashd rejects with bad-blk-sigops. A miner who produces such a block can split the network: Zebra nodes follow the offending chain while zcashd nodes do not. This issue has been patched in version 4.4.0.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZE
zebra · ZcashFoundation
< 4.4.0 · source: vendor
ZE
Zebrad · Zfnd
before 4.4.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44498
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-44498
Release Notes
https://github.com/ZcashFoundation/zebra/releases/tag/v4.4.0
Vendor Advisory
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-jv4h-j224-23cc
More from zebra
9.3
CVE-2026-52735
ZEBRA: Consensus divergence via P2SH sigop undercount in pure-Rust disabled-opcode parser
9.3
CVE-2026-54496
Missing copy constraint in halo2_gadgets variable-base scalar multiplication allows under-constrained base, breaking Orchard Action circuit soundness
9.1
CVE-2026-44497
ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling due to Stale Buffer
9.1
CVE-2026-41583
ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling
8.7
CVE-2026-52736
ZEBRA: Block suppression via NU5 same-header body poisoning of sent-hash cache