CVE-2026-41584

rk Identity Point Panic in Transaction Verification

Orchard transactions contain a rk field which is a randomized validating key and also an elliptic curve point. The Zcash specification allows the field to be the identity (a "zero" value), however, the orchard crate which is used to verify Orchard proofs would panic when fed a rk with the identity value. Thus an attacker could send a crafted transaction that would make a Zebra node crash.

Severity

Critical - This is a Denial of Service Vulnerability that could allow an attacker to crash Zebra nodes.

Affected Versions

All Zebra versions prior to version 4.3.1.

Description

The vulnerability exists in the circuits.rs file of the orchard crate; it attempts to get the coordinates of the rk value and calls unwrap() on the results, which causes a panic if rk is the identity.

Zebra parses rk as a byte vector; it creates an Orchard "bundle" using the orchard crate and then calls the same crate to verify it, triggering the panic.

An attacker could exploit this by:

1. Creating a transaction with a identity rk
2. Submitting it to a Zebra node, making it crash

Fixed Versions

This issue is fixed in Zebra 4.3.1.

The fix was agreed with zcashd developers (which has the same issue) to not allow the identity rk anymore and change the specification as such. Zebra now does this when parsing a transaction. This was deemed easier than fixing the issue in orchard, which would make the bug public before the nodes could be patched.

Mitigation

Users should upgrade to Zebra 4.3.1 or later immediately.

There are no known workarounds for this issue. Immediate upgrade is the only way to ensure the node remains not vulnerable to denial of service.

Credits

Thanks to Alex “Scalar” Sol for finding and reporting the issue.

Denial of Service

• Attack Vector: Network.
• Effect: Node crash.
• Scope: Any impacted Zebra node.

CVE-2026-41584 has a CVSS score of 7.5 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.3.1, 6.0.2); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-41584? CVE-2026-41584 is a critical-severity security vulnerability in zebrad (rust), affecting versions < 4.3.1. It is fixed in 4.3.1, 6.0.2.
2. How severe is CVE-2026-41584? CVE-2026-41584 has a CVSS score of 7.5 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2026-41584?
   • zebrad (rust) (versions < 4.3.1)
   • zebra-chain (rust) (versions < 6.0.2)
4. Is there a fix for CVE-2026-41584? Yes. CVE-2026-41584 is fixed in 4.3.1, 6.0.2. Upgrade to this version or later.
5. Is CVE-2026-41584 exploitable, and should I be worried? Whether CVE-2026-41584 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-41584 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-41584?
   • Upgrade zebrad to 4.3.1 or later
   • Upgrade zebra-chain to 6.0.2 or later