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HIGH severity

CVE-2026-47249 — klever-go

HIGH

CVE-2026-47249 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in github.com/klever-io/klever-go. A fix is available for github.com/klever-io/klever-go — see the affected versions and patch details below.

Klever-Go KVM: Hash-array amplification in P2P resolver request handling

Also known asGHSA-w342-mj6g-v9c4GO-2026-5685
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 17, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-47249.

EPSS Exploitation Probability

via FIRST.org ↗
0.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs41th percentile — riskier than 41% of all scored CVEsHighest risk
0.00%0.33%0.66%0.99%0.3%0.5%0.5%Sep 26Oct 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-47249 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 390,807 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐹github.com/klever-io/klever-go

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

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:

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 Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/klever-io/klever-goall versions1.7.18go get github.com/klever-io/klever-go@v1.7.18

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/klever-io/klever-go, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update github.com/klever-io/klever-go to 1.7.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47249 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### 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 r
O3 Security · Impact-Aware SCA

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CVE-2026-47249: klever-go — Fixed in 1.7.18