# CVE-2026-104432: Zebra before 6.3.0 False Readiness via Discarded One-Hash FindBlocks Response

> Attackers can cause Zebra nodes to falsely report readiness, bypassing health checks while remaining unsynchronized with the blockchain tip.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Oct 2026
- **Updated:** 6 Oct 2026
- **Also known as:** GHSA-h8m8-844p-v3m9, GHSA-x44x-7hf5-cfvh

## What is CVE-2026-104432?

CVE-2026-104432 is a medium-severity vulnerability in ZcashFoundation zebra, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-754 (Improper Check for Unusual or Exceptional Conditions)

## Which versions are affected by CVE-2026-104432?


## How do I fix CVE-2026-104432?

No fix has been published for CVE-2026-104432 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-104432 being exploited?

There is no known exploitation of CVE-2026-104432 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104432 and fix it if it is affected.

What it is: CVE-2026-104432 is a medium-severity vulnerability in ZcashFoundation zebra, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-104432 in the wild and no public exploit code.

Affected product: ZcashFoundation zebra. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-104432/ (Markdown: https://insights.sbomify.com/CVE-2026-104432/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104432
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104432
- OSV: https://osv.dev/vulnerability/CVE-2026-104432

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104432/
Summaries are generated and may contain mistakes; the official description above is the record.