Zebra before 6.0.0 Denial of Service via Synchronous Script FFI Verification
Priority MEDIUM 44CWE-405Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
Zebra before 6.0.0 contains a denial of service vulnerability that allows unauthenticated peers to stall Tokio workers by submitting mempool transactions requiring expensive synchronous script verification. Attackers can send non-standard high-sigop P2SH transactions that reach CachedFfiTransaction::is_valid() before standardness checks, saturating the verifier buffer and rendering the node unresponsive.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00343 28th percentileScored 2026-11-07
Fix Fixed zebra (ZcashFoundation): 6.0.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- 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 6.0.0 | 6.0.0 | Patch available | CNA |
- zebra VendorZcashFoundation Affected before 6.0.0 Fixed in 6.0.0 Patch available CNA
Remediation
- Fix · CNA zebra (ZcashFoundation) Fixed in 6.0.0
Timeline
- 2026-10-02 Threatist record created from CVE-2026-104431
- 2026-10-03 Alias added: GHSA-ppfj-6m85-xq47
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-2026-30136 ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling CVSS 4.0CRITICAL 9.3
- TI-2026-37853 ZEBRA: Consensus divergence via P2SH sigop undercount in pure-Rust disabled-opcode parser CVSS 4.0CRITICAL 9.3
Sources
- CVE-2026-104431 · CVE Program
- CVE-2026-104431 · NVD
- FIRST EPSS
- GHSA-ppfj-6m85-xq47 · GitHub Advisory Database · CC BY 4.0
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