Resource exhaustion in Zcashfoundation Zebra
CVE-2026-44500
ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.4.0, prior to zebra-chain version 7.0.0, and prior to zebra-network version 6.0.0, several inbound deserialization paths in Zebra allocated buffers sized against generic transport or block-size ceilings before the tighter protocol or consensus limits were enforced. An unauthenticated or post-handshake peer could therefore force the node to preallocate and parse for orders of magnitude more data than the protocol intended, across headers messages, equihash solutions in block headers, Sapling spend vectors in V5/V4 transactions, and coinbase script bytes in blocks. This issue has been patched in zebrad version 4.4.0, zebra-chain version 7.0.0, and zebra-network version 6.0.0.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.004 (34.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 34.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.001
Affected products
- Zcashfoundation Zebra — versions zebrad < 4.4.0, zebra-chain < 7.0.0, zebra-network < 6.0.0
- Zfnd Zebra-Chain
- Zfnd Zebrad
- Zfnd Zebra-Network
Weakness classification (CWE)
References
- github.com/ZcashFoundation/zebra/security/advisories/GHSA-438q-jx8f-cccv (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-44500?
- CVE-2026-44500 is a medium-severity vulnerability in Zcashfoundation Zebra, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.3/10. Published 2026-05-08.
- How severe is CVE-2026-44500?
- Medium severity. CVSS v3 base score is 5.3 out of 10.