Medium severity · published Oct 2, 2026
CVE-2026-104432
Zebra before 6.3.0 False Readiness via Discarded One-Hash FindBlocks Response
5.3
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 23% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZE
zebra · ZcashFoundation
before 6.3.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-104432
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-104432
vendor-advisory
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-h8m8-844p-v3m9
third-party-advisory
https://www.vulncheck.com/advisories/zebra-before-6.3.0-false-readiness-via-discarded-one-hash-findblocks-response
More from zebra
9.3
CVE-2026-52735
ZEBRA: Consensus divergence via P2SH sigop undercount in pure-Rust disabled-opcode parser
9.3
CVE-2026-54496
Missing copy constraint in halo2_gadgets variable-base scalar multiplication allows under-constrained base, breaking Orchard Action circuit soundness
9.1
CVE-2026-44497
ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling due to Stale Buffer
9.1
CVE-2026-41583
ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling
8.7
CVE-2026-52736
ZEBRA: Block suppression via NU5 same-header body poisoning of sent-hash cache