CVE-2026-52878 in Klever-Go
Summary
by MITRE • 08/08/2026
Klever-Go is the Go implementation of the Klever blockchain protocol. Versions 1.7.14 through 1.7.17 are vulnerable to a nil-pointer panic triggered by a protobuf Transaction whose embedded RawData sub-message is omitted. This omission causes RawData to decode to nil. Every transaction gossiped on the Klever-Go P2P network is decoded and validated synchronously inside the libp2p pubsub topic-validator callback, where txVersionChecker.CheckTxVersion dereferences tx.RawData.Version with no nil check. Because the libp2p pubsub callback, the underlying go-libp2p-pubsub validation worker, and Klever's own network/p2p layer install no recover(), the panic propagates and crashes the entire node process. The attacker payload is a 3-byte protobuf message; no validator key, stake, funds, or on-chain account is required, and delivery aimed at enough of the BLS validator set can halt block production, resulting in a chain halt. This issue has been fixed in version 1.7.18.
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Analysis
by VulDB Data Team • 08/08/2026
The vulnerability in Klever-Go versions 1.7.14 through 1.7.17 represents a critical denial-of-service condition stemming from improper handling of protobuf message structures within the transaction validation process. This flaw resides in the protocol's P2P network layer where transactions are processed synchronously through libp2p pubsub topic-validator callbacks, creating a single point of failure that can cascade into complete node crashes. The root cause involves the protobuf deserialization logic failing to validate the presence of required sub-messages before attempting to access their fields, specifically when the RawData embedded message is omitted from incoming transactions.
The technical implementation flaw manifests as a nil-pointer dereference during transaction validation, where the txVersionChecker.CheckTxVersion function attempts to access tx.RawData.Version without performing a nil check on the RawData field. This violates fundamental defensive programming practices and creates an exploitable condition that can be triggered by malformed protobuf messages. The vulnerability's impact extends beyond individual node crashes to threaten network-wide stability since every transaction received through the P2P network undergoes this synchronous validation process within the libp2p pubsub framework.
The operational consequences of this vulnerability are severe given that the attack requires only a minimal 3-byte protobuf payload to trigger the panic condition, eliminating any need for validator keys, stake, or on-chain account credentials. The attacker can construct malicious transactions that will cause nodes to crash upon validation, potentially affecting a sufficient number of BLS validators to halt block production entirely and bring the entire blockchain network to a standstill. This represents a classic remote code execution vulnerability through denial-of-service mechanisms where network availability is compromised rather than data integrity.
The absence of proper error handling and recovery mechanisms within the libp2p pubsub callback chain, along with the lack of recover() statements in both the underlying go-libp2p-pubsub validation workers and Klever's own network/p2p layer, ensures that any panic condition propagates throughout the entire node process without graceful degradation. This architectural oversight creates a complete system failure scenario where the vulnerability can be exploited by anyone with access to the network, making it particularly dangerous in permissionless environments. The fix implemented in version 1.7.18 addresses this by introducing proper nil checking mechanisms before dereferencing the RawData field, aligning with CWE-476 which specifically addresses null pointer dereference conditions.
This vulnerability demonstrates how protobuf parsing errors can lead to critical system instability when combined with synchronous processing patterns in distributed systems, highlighting the importance of defensive programming practices and proper error handling in network validation layers. The ATT&CK framework would categorize this as a denial-of-service attack leveraging protocol implementation flaws, while the CWE classification places it firmly within the realm of null pointer dereference vulnerabilities that compromise system availability. The remediation approach taken by Klever-Go developers represents a standard defensive programming solution involving proper input validation and nil checking before field access operations.