ZEBRA: Finalized address balance credit-first overflow on consensus-valid blocks
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-248.
Summary
ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, a consensus-valid block containing a long chain of transparent self-spends to one address can permanently halt Zebra nodes. In zebra-state/src/service/finalized_state/zebra_db/transparent.rs, the finalized-state writer originally applied every newly created output as a credit before applying any spent-output debit from the same block. That credit-first ordering can make the intermediate per-address balance exceed MAX_MONEY even though the final net balance is valid, causing an expect-based panic under the panic equals abort release profile. Because zcashd accepts the triggering block and Zebra encounters it again after every restart, the halt persists until patched software is deployed; exploitation requires mining the specially constructed block and temporarily committing sufficient ZEC to the self-spend chain. This issue is fixed in version 4.5.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| ZcashFoundation | zebra | before 4.5.0 | 4.5.0 | Patch available | CNA |
| ZcashFoundation | zebra-state | before 7.0.0 | 7.0.0 | Patch available | CNA |
| — | zebra-state (crates.io) | before 7.0.0 | 7.0.0 | Patch available | GHSA-w834-cf6p-9m9w |
| — | zebrad (crates.io) | before 4.5.0 | 4.5.0 | Patch available | GHSA-w834-cf6p-9m9w |
- zebra VendorZcashFoundation Affected before 4.5.0 Fixed in 4.5.0 Patch available CNA
- zebra-state VendorZcashFoundation Affected before 7.0.0 Fixed in 7.0.0 Patch available CNA
- zebra-state (crates.io) Vendor— Affected before 7.0.0 Fixed in 7.0.0 Patch available GHSA-w834-cf6p-9m9w
- zebrad (crates.io) Vendor— Affected before 4.5.0 Fixed in 4.5.0 Patch available GHSA-w834-cf6p-9m9w
Remediation
- Fix · CNA zebra (ZcashFoundation) Fixed in 4.5.0
- Fix · CNA zebra-state (ZcashFoundation) Fixed in 7.0.0
- Fix · GHSA-w834-cf6p-9m9w zebra-state (crates.io) Fixed in 7.0.0 Advisory →
- Fix · GHSA-w834-cf6p-9m9w zebrad (crates.io) Fixed in 4.5.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-52738
- 2026-10-03 Alias added: GHSA-w834-cf6p-9m9w
References
More ZcashFoundation vulnerabilities
- TI-2026-66079 Zebra before 4.4.0 Consensus Split via SIGHASH_SINGLE Missing-Output Handling CVSS 4.0HIGH 8.3
- TI-2026-37850 ZEBRA: Mempool transaction admission denial via single-peer inbound queue saturation CVSS 3.1MEDIUM 5.3
- TI-2026-71182 Improper block validation in Zebra gossip lets peers drop new blocks CVSS 4.0MEDIUM 6.3
- TI-2026-29537 Zebra: addr/addrv2 Deserialization Resource Exhaustion CVSS 4.0MEDIUM 6.3
- TI-2026-86702 Incomplete cleanup in Zebra lets peers stall initial sync CVSS 4.0HIGH 8.7
- TI-2026-86701 Quadratic signature hashing in Zcash Zebra enables denial of service CVSS 4.0HIGH 8.7
Sources
- CVE-2026-52738 · CVE Program
- CVE-2026-52738 · NVD
- FIRST EPSS
- GHSA-w834-cf6p-9m9w · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences