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

Severity: low (CVSS 3.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-14 · updated 2026-09-30
Weakness: CWE-125

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.

Affected products

nimiq core-rs-albatross: before 1.6.0

References

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