Summary
Workarounds
No Workaround, although requesting the genesis batch set is not used during normal operation.
Resources
See PR.
Impact
A remote peer can crash any full node by sending a RequestBatchSet message containing the genesis block's hash. The handler calls get_epoch_chunks which iterates backwards through macro blocks using Policy::macro_block_before. When it reaches the genesis block number, macro_block_before panics with "No macro blocks before genesis block".
CVE-2026-46543 has a CVSS score of 5.3 (Medium). 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 (1.5.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
The patch for this vulnerability is formally released as part of v1.5.0.
Frequently Asked Questions
- What is CVE-2026-46543? CVE-2026-46543 is a medium-severity security vulnerability in nimiq-blockchain (rust), affecting versions < 1.5.0. It is fixed in 1.5.0.
- How severe is CVE-2026-46543? CVE-2026-46543 has a CVSS score of 5.3 (Medium). 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.
- Which versions of nimiq-blockchain are affected by CVE-2026-46543? nimiq-blockchain (rust) versions < 1.5.0 is affected.
- Is there a fix for CVE-2026-46543? Yes. CVE-2026-46543 is fixed in 1.5.0. Upgrade to this version or later.
- Is CVE-2026-46543 exploitable, and should I be worried? Whether CVE-2026-46543 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
- What actually determines whether CVE-2026-46543 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.
- How do I fix CVE-2026-46543? Upgrade
nimiq-blockchainto 1.5.0 or later.