Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, the KleverUpdateAccountPermission built-in authorizes replacement of a target account's permissions by checking attacker-controlled vmInput.RecipientAddr instead of authenticated vmInput.CallerAddr. An attacker-controlled contract can choose a victim account with configured permissions as RecipientAddr, and contractHasValidPermission can accept the victim's default self-signer as authorization. UpdatePermission can then replace the victim's entire permission set with attacker-supplied Owner permissions, enabling asset theft or permanent lockout without a victim key or signature. Accounts without stored permissions and the native transaction path are not affected. This issue is fixed in version 1.7.20.
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, indexer/common.go serializedDataForUpdateAccounts places the attacker-controlled acc.Name value into an Elasticsearch _bulk JSON and NDJSON request without escaping it. The SetAccountName transaction accepts valid UTF-8 account names containing quotes, backslashes, and newlines, and the resulting name is stored in consensus account state. When an indexer processes the account, those characters can break the JSON string, reject a bulk batch, or inject additional bulk actions that create, overwrite, or delete documents in indices writable by the indexer. The persistent state value is replayed by new or historical indexers, and direct access to the indexing host or Elasticsearch port is not required. This issue is fixed in version 1.7.20.
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, core/kapp/validators/validators.go Register and the runtime validator update path accept a submitted BLSPublicKey without curve, prime-order subgroup, or nonzero validation. When a validator with a malformed key becomes eligible and is selected into a consensus group, MultiSigner.Reset and the corresponding signature verification creation path cannot deserialize the group key and cancel the slot. This causes repeated missed rounds and throughput degradation, and a network whose consensus group equals the eligible validator set can halt completely. Genesis validation is not affected because that path already performs CheckPublicKeyValid. This issue is fixed in version 1.7.20.
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, the default-open GET /subscribe endpoint in network/api/websocket/routes.go accepts unauthenticated WebSocket clients with permissive origin handling, does not call SetReadLimit to bound message size, and has no live-connection cap. SocketHub.HandleClientInsertion also accepts an unbounded address list that grows addressSubscription, and client.loopIn continues reading without a size limit, allowing one client to grow subscription maps or many clients to retain goroutines, buffered channels, and descriptors. The global HTTP request throttler does not count upgraded live WebSocket connections. Because the REST and WebSocket API runs in the node process, memory or scheduler exhaustion can crash the node and interrupt P2P and consensus participation. This issue is fixed in version 1.7.20.
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, the default-open GET /log WebSocket route configured in config/node/api.yaml and registered by network/api/api.go does not require authentication. The first client message is parsed as a logger Profile in network/api/logs/logSender.go and applied process-wide through Profile.Apply, allowing a remote client to change global log levels and formatting options until the connection closes. The same connection is registered as a log observer and can receive live process logs. An attacker can suppress normal logs, increase verbosity, distort operator visibility, and access operational information without credentials. This issue is fixed in version 1.7.20.
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, the native marketplace function core/kapp/market/market.go Buy does not check IsClaimed before accepting a bid. A seller can use the Claim seller-accept branch to settle a resting-bid auction while leaving the claimed order loadable with a future EndTime and stale CurrentBid and CurrentBidder values. A later bidder can submit a higher bid, be debited, and cause the previous bidder to receive a refund even though the NFT has already been delivered. Because Claim and CancelOrder reject the later bidder when IsClaimed is true, the later bidder cannot obtain the NFT or recover the funds. This issue is fixed in version 1.7.20.
CVE-2026-55764 is an integer overflow vulnerability in klever-io's klever-go blockchain protocol implementation. Before version 1.7.19, a mint-role holder could bypass the finite per-nonce MaxSupply limit on semi-fungible token quantity additions. The flaw occurs because the code increments the circulation count before checking for overflow, allowing a large positive amount to wrap the circulation value negative and bypass the maximum supply check. This leads to crediting approximately MaxInt64 units and corrupting the on-chain counter. The issue is fixed in version 1.7.19.
CVE-2026-55763 is a high-severity vulnerability in klever-go, the Go implementation of the Klever blockchain protocol. Prior to version 1.7.19, a logic flaw in the processPercentageRoyaltiesTransfer function allows a 100% royalty split to be processed without debiting the source account, resulting in unbounded off-the-books inflation of the KDA token supply. This occurs because the function returns early when royaltiesToPay reaches zero, before subtracting the amount from the sender's balance. The issue is fixed in version 1.7.19.
CVE-2026-54755 is a critical integer overflow vulnerability in klever-go, the Go implementation of the Klever blockchain protocol. Prior to version 1.7.19, crafted split-royalty values can cause uint32 accumulator wraparound, bypassing validation checks. This allows creation of unbacked KLV or other assets during asset transfers, marketplace purchases, or ITO purchases. The issue is fixed in version 1.7.19.
CVE-2026-54754 is a critical integer underflow vulnerability in klever-io's klever-go blockchain protocol implementation prior to version 1.7.19. It involves marketplace settlement logic where combined referral and royalty percentages can exceed the bid amount, causing the system to credit more tokens than the buyer paid. This leads to creation of unbacked currency and corruption of token supply integrity. The issue is fixed in version 1.7.19.
Klever-Go is the Go implementation of the Klever blockchain protocol. Versions from 1.7.14 through 1.7.17 are vulnerable to a remotely triggerable denial of service. Both REST APIs are started with the Gin Engine.Run convenience method, which serves requests through Go's default HTTP server with no ReadHeaderTimeout, ReadTimeout, or MaxHeaderBytes configured. As a result, incoming connections that never complete their request headers are held open indefinitely. When a REST listener is reachable beyond localhost through the documented all-interface bind or a Docker port-publish deployment, a single unauthenticated client can open many slow-header connections and hold them open until server file descriptors are exhausted, preventing the API from accepting new connections. This renders the REST API unavailable to legitimate clients. This issue is fixed in version 1.7.18.
Klever-Go is the Go implementation of the Klever blockchain protocol. In versions 1.7.14 through 1.7.17, the direct-message ingress handler spawns a new goroutine for every incoming direct message before the processor-level antiflood layer makes any admission decision, with no semaphore, throttler, or bound on the number of concurrent in-flight spawns. Because the antiflood check runs inside the spawned goroutine rather than before it, a single connected peer can open a direct-send stream and send a stream of well-formed messages to force unbounded goroutine creation, where each goroutine allocates its own stack and holds a message reference until processing completes, adding scheduler and garbage-collection pressure faster than the runtime can drain it. This lets one peer degrade the node's availability and its ability to process legitimate traffic, resulting in a remotely triggerable denial of service. The issue is fixed in 1.7.18.
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.
Klever-Go is the Go implementation of the Klever blockchain protocol. In versions prior to 1.7.18, the account-data trie syncers are vulnerable to a resource-exhaustion flaw that leaks bounded throttler slots on error paths. In syncDataTrie() (in both userAccountsSyncer.go and kappAccountsSyncer.go), StartProcessing() reserves a slot from the NumGoRoutinesThrottler, but the corresponding EndProcessing() is only called on the success path and on the duplicate-root early return. As a result, any error from trie.NewTrie(), trie.NewTrieSyncer(), or trieSyncer.StartSyncing() (including the network-dependent timeout path) permanently consumes one slot for the lifetime of the throttler. An attacker who can repeatedly cause trie-node sync failures or timeouts during bootstrap can exhaust the bounded throttler, after which further account-data trie syncs stop making progress and SyncAccounts() returns a timeout. Because epoch bootstrap in syncUserAccountsState() and syncKappAccountsState() aborts on any such error, this causes bootstrap to fail, a core availability issue affecting fresh, restarting, or resyncing nodes and validators. This issue is fixed in version 1.7.18.
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.18, the P2P resolver request handling logic is vulnerable to hash-array amplification. A connected peer can send a compressed RequestDataType_HashArrayType direct request that is only 442 bytes on the wire but expands into 200,000 decoded hash entries inside the resolver path. The resolver's antiflood logic counts only a single logical message and the compressed wire size, and while Batch.Decompress() caps the decompressed byte size, it never limits the number of decoded repeated-field items. As a result, both TxResolver and TrieNodeResolver preallocate and iterate over the entire unchecked set of decoded hashes, causing remote memory and CPU amplification against any node that accepts P2P peer connections. This issue is fixed in version 1.7.18.
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, header signature verification counts the unused padding bits of the PubKeysBitmap toward the two-thirds validator quorum. These padding bits do not correspond to any validator and are ignored by the actual BLS aggregate-signature check, so a malicious or compromised block producer can set them to reach the required quorum while gathering fewer genuine validator signatures than the protocol demands. As a result, nodes that import or intercept the header accept it as correctly signed without a real two-thirds quorum, weakening consensus safety and undermining finality. This issue is fixed in version 1.7.20.
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.17, KVM exposes `ExecuteReadOnlyWithTypedArguments` as a read-only execution mechanism. The hook saves the previous read-only state, sets `runtime.SetReadOnly(true)`, executes the destination context, and then restores the previous read-only state. However, the indirect contract delete and upgrade paths do not reject execution when `runtime.ReadOnly()` is true. As a result, a contract reached through read-only execution can call the production delete hook for a target contract it owns. The delete path appends the target address to `vmOutput.DeletedAccounts`, the output context merges `DeletedAccounts` into the caller output, and the smart contract processor later processes the VM output by deleting accounts listed in that field. The root cause is that read-only mode is applied as runtime state, but not enforced by the state-changing delete and upgrade host-core paths. This breaks the expected isolation boundary for workflows that rely on read-only calls to inspect another contract without allowing that callee to produce state-changing VM output. The issue is fixed in v1.7.17. Contract delete and upgrade host-core paths now reject execution when `runtime.ReadOnly()` is true. The invariant is regression-tested for delete, upgrade, storage writes, value transfers, and any VM output field that can later mutate chain state.
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.17, a remote, unauthenticated denial-of-service vulnerability in Batch.Decompress (data/batch/batch.go) allows any peer that participates in a topic served by MultiDataInterceptor to allocate multi-gigabyte heaps on the receiving node from a sub-50 KiB gossip payload. A single packet is sufficient to OOM-kill a validator with conventional memory provisioning. Fleet-wide application affects chain liveness. This vulnerability is fixed in 1.7.17.