CVE-2026-109363

high

ZcashFoundation Zebra 6.4.0 before 6.4.2 parses version 6 transactions carrying a pre-NU6.3 consensus branch ID, but the size computation during UnminedTx cons…

ZcashFoundation Zebra 6.4.0 before 6.4.2 parses version 6 transactions carrying a pre-NU6.3 consensus branch ID, but the size computation during UnminedTx construction treats re-serialization of the Orchard bundle as infallible, so the resulting error trips an expect that aborts zebrad. Unauthenticated peers can send a single pre-handshake tx message to crash the node, and can repeat this after each restart.

CVSS

7.5

7.5 (CVSS v3.1)

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

Severity source: NVD CVSS v3.1 (disclosure@vulncheck.com)

Timeline (UTC)

Published: 2026-10-12 17:17

Modified: 2026-10-15 20:31

NVD status: Deferred

Last synced 1 day ago

Verified against the source API 2026-10-27 06:58 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

Not reported by the source (unknown — not "none").

Weakness classification (CWE)

CWE-617

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

https://github.com/ZcashFoundation/zebra/commit/008abac5c99e872f283450d596d95e37851df49a disclosure@vulncheck.com
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-h5rr-8pqv-grp9 disclosure@vulncheck.com
https://www.vulncheck.com/advisories/zebra-6.4.0-before-6.4.2-denial-of-service-via-malfor... disclosure@vulncheck.com

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 06:58 UTC · record ↗

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