Quick answers
- Is CVE-2026-104432 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-104432 being exploited in the wild.
- How severe is CVE-2026-104432?
- Medium severity, with a CVSS score of 5.3, published 2 October 2026.
- Which products and versions are affected?
- Zcash Foundation Zebra before 6.3.0.
- Is there a fix for CVE-2026-104432?
- Yes: fixed in 6.3.0. Until then: Monitor the node's chain tip height against the network tip as an independent check, rather than relying solely on the /ready endpoint to detect staleness. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-104432 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-104432?
- Check whether you run Zcash Foundation Zebra at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 6.3.0
Monitor the node's chain tip height against the network tip as an independent check, rather than relying solely on the /ready endpoint to detect staleness.
Technical details
An improper exception check in ChainSync::obtain_tips (CWE-754) discards valid one-hash FindBlocks responses, treating them as invalid when they contain only the node's next block hash. This produces a zero-length sync sample that causes SyncStatus::is_close_to_tip() to incorrectly return true, making the /ready endpoint return HTTP 200 OK while the node remains within the ready_max_blocks_behind window (default 2 blocks). The vulnerability affects mainnet and testnet nodes under default configuration and requires no user interaction or authentication.
Affected products
- Zcash Foundation Zebra before 6.3.0
Timeline
- 2026-08-17: disclosed
- 2026-08-17: patched: v6.3.0 released
- 2026-10-02: advisory