# CVE-2026-54542: Nimiq: Out-of-bounds panic in KeyNibbles::Add from oversized child suffix in a deserialized proof

> A malicious sync peer can crash a Nimiq node by sending a crafted TrieChunk, causing an out-of-bounds panic during state synchronization.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-5rg2-xv9j-gv5p

## What is CVE-2026-54542?

CVE-2026-54542 is a low-severity denial of service vulnerability in nimiq core-rs-albatross, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Nimiq is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. Prior to 1.6.0, a malicious state-sync peer can crash a syncing node by sending a crafted TrieChunk whose proof contains a TrieNodeChild suffix that is individually valid but exceeds the 63-byte KeyNibbles backing array when combined with the parent key. KeyNibbles::Add in primitives/src/key_nibbles.rs performs the combined slice operation without checking the total length, and the input reaches put_chunk, TrieNodeChild::key, and TrieNodeChild::is_stump before proof.verify, so the attacker does not need a valid cryptographic proof. Exploitation requires the attacker to be selected as the victim's sync peer during state sync. The resulting out-of-bounds panic is transient because the node restarts and resynchronizes. This issue is fixed in version 1.6.0.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-54542?

2 open source packages ship an affected version, including nimiq-primitives.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nimiq-primitives` | crates.io | All versions | 1.6.0 |
| `nimiq-primitives` | crates.io | All versions | 1.6.0 |

## How do I fix CVE-2026-54542?

Upgrade nimiq-primitives to 1.6.0 or later.

## Is CVE-2026-54542 being exploited?

There is no known exploitation of CVE-2026-54542 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54542 and fix it if it is affected.

What it is: CVE-2026-54542 is a low-severity denial of service vulnerability in nimiq core-rs-albatross, published on 14 Sep 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-2026-54542 in the wild and no public exploit code.

Affected packages and fixed versions:
- nimiq-primitives (crates.io): affected all versions; fixed in 1.6.0
- nimiq-primitives (crates.io): affected all versions; fixed in 1.6.0

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-2026-54542/ (Markdown: https://insights.sbomify.com/CVE-2026-54542/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54542
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54542
- OSV: https://osv.dev/vulnerability/CVE-2026-54542

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54542/
Summaries are generated and may contain mistakes; the official description above is the record.