CVE-2026-54542 is a low-severity (CVSS 3.7) remote code execution vulnerability in nimiq-primitives. O3 Security confirms whether CVE-2026-54542 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
nimiq-primitives: Out-of-bounds panic in KeyNibbles::Add from oversized child suffix in a deserialized proof
Real-World Exposure
nimiq-primitivesReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Impact
A malicious peer acting as a state-sync source can crash a syncing node with a crafted TrieChunk whose proof contains a TrieNodeChild whose suffix, when concatenated with the parent key via KeyNibbles::Add, exceeds the fixed 63-byte backing array. Add (primitives/src/key_nibbles.rs:332 / :341) indexes bytes[self.bytes_len()..self.bytes_len() + other.bytes_len()] with no combined-length check, causing an out-of-bounds slice panic (both the even- and odd-length branches).
KeyNibbles deserialization validates only the individual length <= 126, not the combined parent + suffix length. The panic occurs at put_chunk → child.key() → is_stump() → +, i.e. before proof.verify(), so no valid proof is required. As with the related child_index issue, exploitation requires being the victim's sync peer during state sync, and the resulting crash is transient (the node restarts and re-syncs).
Affected: core-rs-albatross <= 1.5.1 (nimiq-primitives).
Patches
Fixed in 1.6.0 via https://github.com/nimiq/core-rs-albatross/pull/3790 (commit eabfc3e2), which guards key-nibble concatenation against exceeding the maximum length instead of indexing out of bounds.
Workarounds
None other than syncing only from trusted peers. Upgrade to 1.6.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | nimiq-primitives | all versions | 1.6.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nimiq-primitives. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update nimiq-primitives to 1.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54542 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-54542 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-54542. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-54542 in your dependencies?
O3 detects CVE-2026-54542 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.