CVE-2026-104432

MEDIUM 5.3

Zebra before 6.3.0 False Readiness via Discarded One-Hash FindBlocks Response

CVSS Score

5.3

EPSS Score

0.0%

EPSS Percentile

0th

Zebra before 6.3.0 contains an improper exceptional condition check in ChainSync::obtain_tips that discards valid one-hash FindBlocks responses, falsely reporting close-to-tip status. Peers returning only the next block hash cause a zero-length sync sample, making the /ready endpoint return 200 OK while the node remains behind the tip.

CWE	CWE-754
Vendor	zcashfoundation
Product	zebra
Published	Oct 2, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Affected Versions

ZcashFoundation / zebra

0 < 6.3.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-h8m8-844p-v3m9 vulncheck.com: https://www.vulncheck.com/advisories/zebra-before-6.3.0-false-readiness-via-discarded-one-hash-findblocks-response

Credits

🔍 Maakai123 oxarbitrage