CVE-2026-109365

LOW 3.7

Zebra before 6.4.0 Denial of Service via Same-Hash Forged Block Bodies

CVSS Score

3.7

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-345
Vendor	zcashfoundation
Product	zebra
Published	Oct 12, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Affected Versions

ZcashFoundation / zebra

0 < 6.4.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-3c94-hf7p-g5mf vulncheck.com: https://www.vulncheck.com/advisories/zebra-before-6.4.0-denial-of-service-via-same-hash-forged-block-bodies

Credits

🔍 ouicate conradoplg mpguerra