# CVE-2026-44497: ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling due to Stale Buffer

> Attackers can cause consensus divergence between Zebra and zcashd nodes by exploiting stale buffer handling in sighash computation.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 May 2026
- **Updated:** 8 May 2026
- **Also known as:** GHSA-gq4h-3grw-2rhv

## What is CVE-2026-44497?

CVE-2026-44497 is a critical vulnerability in ZcashFoundation zebra, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.4.0 and prior to zebra-script version 6.0.0, the fix for CVE-2026-41583 introduced a separate issue due to insufficient error handling of the case where the sighash type is invalid, during sighash computation. Instead of returning an error, the normal flow would resume, and the input sighash buffer would be left untouched. In scenarios where a previous signature validation could leave a valid sighash in the buffer, an invalid hash-type could be incorrectly accepted, which would create a consensus split between Zebra and zcashd nodes. This issue has been patched in zebrad version 4.4.0 and zebra-script version 6.0.0.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2026-44497?

4 open source packages ship an affected version, including zebra-script and zebrad. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `zebra-script` | crates.io | All versions | 6.0.0 |
| `zebra-script` | crates.io | All versions | 6.0.0 |
| `zebrad` | crates.io | All versions | 4.4.0 |
| `zebrad` | crates.io | All versions | 4.4.0 |

Products: Zfnd Zebra-Script, Zfnd Zebrad.

## How do I fix CVE-2026-44497?

Upgrade zebra-script to 6.0.0 or later.

## Is CVE-2026-44497 being exploited?

There is no known exploitation of CVE-2026-44497 in the wild and no public exploit code.

## Other vulnerabilities in ZcashFoundation zebra

- [CVE-2026-41583](https://insights.sbomify.com/CVE-2026-41583/): ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44497 and fix it if it is affected.

What it is: CVE-2026-44497 is a critical vulnerability in ZcashFoundation zebra, published on 8 May 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-2026-44497 in the wild and no public exploit code.

Affected packages and fixed versions:
- zebra-script (crates.io): affected all versions; fixed in 6.0.0
- zebra-script (crates.io): affected all versions; fixed in 6.0.0
- zebrad (crates.io): affected all versions; fixed in 4.4.0
- zebrad (crates.io): affected all versions; fixed in 4.4.0

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-2026-44497/ (Markdown: https://insights.sbomify.com/CVE-2026-44497/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44497
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44497
- OSV: https://osv.dev/vulnerability/CVE-2026-44497

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44497/
Summaries are generated and may contain mistakes; the official description above is the record.