GHSA-w342-mj6g-v9c4 CVE-2026-47249 GO-2026-5685
Klever-Go KVM: Hash-array amplification in P2P resolver request handling
- Severity
- 7.5 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 0.49%
- Chance of exploitation in the next 30 days. Higher than 42.02% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-400 Uncontrolled Resource Consumption
- Fix
1.7.18- Upgrade github.com/klever-io/klever-go to this version or later
Description
Summary
A connected peer can send a compressed RequestDataType_HashArrayType direct request that is only 442 bytes on the wire but expands into 200000 decoded hash entries inside the resolver path. On klever-go v1.7.17, this allows remote memory and CPU amplification against nodes that accept P2P peer connections.
Details
Resolver antiflood logic accounts only one logical message and the compressed wire size in data/retriever/resolvers/messageProcessor.go#L30.
Batch.Decompress() in data/batch/batch.go#L122 enforces an inflated byte cap but does not enforce a decoded repeated-field item cap. After decompression, TxResolver preallocates and iterates all decoded hashes in data/retriever/resolvers/transactionResolver.go#L194, and TrieNodeResolver iterates the same unchecked decoded set in data/retriever/resolvers/trieNodeResolver.go#L108.
Pinned references:
- https://github.com/klever-io/klever-go/blob/333f6ec910906e227705fc5767dc897d8fbfc862/data/retriever/resolvers/messageProcessor.go#L30
- https://github.com/klever-io/klever-go/blob/333f6ec910906e227705fc5767dc897d8fbfc862/data/batch/batch.go#L122
- https://github.com/klever-io/klever-go/blob/333f6ec910906e227705fc5767dc897d8fbfc862/data/retriever/resolvers/transactionResolver.go#L194
- https://github.com/klever-io/klever-go/blob/333f6ec910906e227705fc5767dc897d8fbfc862/data/retriever/resolvers/trieNodeResolver.go#L108
This appears distinct from the public CVE-2026-44697 / GHSA-87m7-qffr-542v, which covered MultiDataInterceptor compressed batch fan-in. This report concerns resolver request paths that remain reachable through real libp2p direct-send plumbing on v1.7.17.
PoC
Reproduced with:
go run auditpoc/request_batch_hash_amplification_poc.go
go test github.com/klever-io/klever-go/auditpoc -run TestRequestBatchHashAmplification_DirectSendReachability -count=1
Observed output:
request wire bytes: 442
fits direct-send limit (983040 bytes): true
tx resolver lookups: 200000
trie resolver lookups: 200000
heap delta before first tx lookup: 17.47 MiB
ok github.com/klever-io/klever-go/auditpoc
The E2E harness registers the victim resolver on the request topic and sends the malicious payload through SendToConnectedPeer() to prove the work amplification survives the real direct-send path.
Impact
A connected peer can convert a sub-kilobyte request into large decode-time memory pressure and synchronous CPU work on the target node. Repeated requests or several concurrent peers can degrade or exhaust validator resources, affecting node availability.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/klever-io/klever-go | < 1.7.18 |
1.7.18 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/klever-io/klever-go Go → 1.7.18
- go
go get github.com/klever-io/klever-go@v1.7.18 && go mod tidy
Severity breakdown
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
References
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-7c7c-373r-gfjj Klever-Go: Elasticsearch bulk / painless injection via on-chain account name -> explorer/indexer data forgery | High | Also affects github.com/klever-io/klever-go |
| GHSA-9wh6-9hq7-9688 Klever-Go: Validator registration accepts an unvalidated BLS public key → consensus liveness DoS | High | Also affects github.com/klever-io/klever-go |
| GHSA-26r5-4mm2-px5c Klever-Go: Zombie-order theft: `Buy` missing `IsClaimed` guard in native marketplace | High | Also affects github.com/klever-io/klever-go |
| GHSA-97cv-x867-6xhm Klever-Go Account takeover: `kleverUpdateAccountPermission` authorizes on attacker-controlled `RecipientAddr` instead of the authenticated caller | High | Also affects github.com/klever-io/klever-go |
| GHSA-4fwh-wrm6-97xm Klever-Go: Unauthenticated WebSocket /subscribe: no read-size limit, no connection cap, permissive origin -> remote node memory/goroutine exhaustion (DoS) | High | Also affects github.com/klever-io/klever-go |
| GHSA-9v8p-frvj-2pcm Klever-Go: /log controls global node logging | High | Also affects github.com/klever-io/klever-go |
| GHSA-mrpp-v6pg-p54x klever-go: SFT add-quantity `int64` overflow bypasses a finite per-nonce MaxSupply | High | Also affects github.com/klever-io/klever-go |
| GHSA-v358-wf77-39xv klever-go: Percentage-transfer royalty skips the source debit at exactly-100% splits | High | Also affects github.com/klever-io/klever-go |
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