VulnerabilityAnalyzed

CVE-2026-44498

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.

CRITICAL 9.2EPSS 0.28%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.28%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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 4.0: 9.2 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.28% probability · 21th percentile
CISA KEV: Not listed
Weakness: CWE-682
Affected: zfnd/zebrad
Source: security-advisories@github.com

References

https://github.com/ZcashFoundation/zebra/releases/tag/v4.4.0Release Notes
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-jv4h-j224-23ccVendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.