Vulnerability in Zcashfoundation Zebra
CVE-2026-123555
Zebra from 2.3.0 before 7.0.0 contains a denial of service vulnerability that allows unauthenticated peers to evade misbehavior scoring by sending transactions or blocks with invalid transparent scripts. Attackers can flood mempool with script-failing transactions or serve forged v5 block bodies with altered scriptSig bytes to exhaust CPU and repeatedly stall block sync.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- Patch Commit (patch)
- GitHub Security Advisory (GHSA-jq45-ghw5-v37x) (vendor-advisory)
- VulnCheck Advisory: Zebra 2.3.0 before 7.0.0 Denial of Service via Unscored Script Verification Failures (third-party-advisory)
Frequently asked questions
- What is CVE-2026-123555?
- CVE-2026-123555 is a high-severity vulnerability in Zcashfoundation Zebra, classified under Improper Handling of Exceptional Conditions. CVSS score: 7.5/10. Published 2026-11-08.
- How severe is CVE-2026-123555?
- High severity. CVSS v3 base score is 7.5 out of 10.