Zebra: addr/addrv2 Deserialization Resource Exhaustion
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- 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-770.
Summary
ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.3.0 and zebra-network version 5.0.1, when deserializing addr or addrv2 messages, which contain vectors of addresses, Zebra would fully deserialize them up to a maximum length (over 233,000) that was derived from the 2 MiB message size limit. This is much larger than the actual limit of 1,000 messages from the specification. Zebra would eventually check that limit but, at that point, the memory for the larger vector was already allocated. An attacker could cause out-of-memory aborts in Zebra by sending multiple such messages over different connections. This vulnerability is fixed in zebrad version 4.3.0 and zebra-network version 5.0.1.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- 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 | zebrad | before 4.3.1 | 4.3.1 | Patch available | CNA |
| ZcashFoundation | zebra-network | before 5.0.1 | 5.0.1 | Patch available | CNA |
| — | zebrad (crates.io) | before 4.3.1 | 4.3.1 | Patch available | GHSA-xr93-pcq3-pxf8 |
| — | zebra-network (crates.io) | before 5.0.1 | 5.0.1 | Patch available | GHSA-xr93-pcq3-pxf8 |
- zebrad VendorZcashFoundation Affected before 4.3.1 Fixed in 4.3.1 Patch available CNA
- zebra-network VendorZcashFoundation Affected before 5.0.1 Fixed in 5.0.1 Patch available CNA
- zebrad (crates.io) Vendor— Affected before 4.3.1 Fixed in 4.3.1 Patch available GHSA-xr93-pcq3-pxf8
- zebra-network (crates.io) Vendor— Affected before 5.0.1 Fixed in 5.0.1 Patch available GHSA-xr93-pcq3-pxf8
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:zfnd:zebra-network:*:*:*:*:*:rust:*:* | before 5.0.1 | Vulnerable | ZcashFoundation |
| cpe:2.3:a:zfnd:zebrad:*:*:*:*:*:rust:*:* | before 4.3.1 | Vulnerable | ZcashFoundation |
- cpe:2.3:a:zfnd:zebra-network:*:*:*:*:*:rust:*:* Versions before 5.0.1 Vulnerable ·ZcashFoundation
- cpe:2.3:a:zfnd:zebrad:*:*:*:*:*:rust:*:* Versions before 4.3.1 Vulnerable ·ZcashFoundation
Remediation
- Fix · CNA zebrad (ZcashFoundation) Fixed in 4.3.1
- Fix · CNA zebra-network (ZcashFoundation) Fixed in 5.0.1
- Fix · GHSA-xr93-pcq3-pxf8 zebrad (crates.io) Fixed in 4.3.1 Advisory →
- Fix · GHSA-xr93-pcq3-pxf8 zebra-network (crates.io) Fixed in 5.0.1 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-40881
- 2026-10-03 Alias added: GHSA-xr93-pcq3-pxf8
References
More ZcashFoundation Zebra-network vulnerabilities
- TI-2026-32434 ZEBRA: Allocation Amplification in Inbound Network Deserializers CVSS 3.1MEDIUM 5.3
Sources
- CVE-2026-40881 · CVE Program
- CVE-2026-40881 · NVD
- FIRST EPSS
- GHSA-xr93-pcq3-pxf8 · GitHub Advisory Database · CC BY 4.0
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