What is CVE-2026-109365?

CVE-2026-109365 is a low-severity vulnerability in Zcashfoundation Zebra, classified under Insufficient Verification of Data Authenticity. CVSS score: 3.7/10. Published 2026-10-12.

How severe is CVE-2026-109365?

Low severity. CVSS v3 base score is 3.7 out of 10.

Vulnerability in Zcashfoundation Zebra

CVE-2026-109365

Zebra before 6.4.0 contains an uncontrolled resource consumption vulnerability that allows unauthenticated peers to force full proof verification by serving forged block bodies with valid header hashes. Attackers can flip authorizing-only bytes such as a coinbase scriptSig, wasting Sapling, Orchard, and Ironwood proof verification without penalty and stalling sync for 67 seconds.

Published 2026-10-12.

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L.

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

Zcashfoundation Zebra

Weakness classification (CWE)

CWE-345 — Insufficient Verification of Data Authenticity

References

github.com/ZcashFoundation/zebra/security/advisories/GHSA-3c94-hf7p-g5mf (vendor-advisory)
www.vulncheck.com/advisories/zebra-before-6.4.0-denial-of-service-via-same-hash… (third-party-advisory)

Frequently asked questions

What is CVE-2026-109365?: CVE-2026-109365 is a low-severity vulnerability in Zcashfoundation Zebra, classified under Insufficient Verification of Data Authenticity. CVSS score: 3.7/10. Published 2026-10-12.
How severe is CVE-2026-109365?: Low severity. CVSS v3 base score is 3.7 out of 10.