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).
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.
None other than syncing only from trusted peers. Upgrade to 1.6.0.
1.6.0Exploitability
AV:NAC:HPR:NUI:NScope
S:UImpact
C:NI:NA:L3.7/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L