Vulnerability-Lookup

CVE-2026-52879 (GCVE-0-2026-52879)

Vulnerability from cvelistv5 – Published: 2026-08-07 22:36 – Updated: 2026-08-10 13:36

Title

Klever-Go: Unbounded goroutine spawn on direct-message ingress enables peer-driven DoS

Summary

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.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-10 13:35 UTC

CWE

CWE-400 - Uncontrolled Resource Consumption
CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M mitre root

References

2 references

URL	Tags
https://github.com/klever-io/klever-go/security/a…	x_refsource_CONFIRM
https://github.com/klever-io/klever-go/releases/t…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
klever-io	klever-go	Affected: >= 1.7.14, < 1.7.18	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-52879

Vulnerability from fkie_nvd - Published: 2026-08-07 23:17 - Updated: 2026-09-09 20:55

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/klever-io/klever-go/releases/tag/v1.7.18
	security-advisories@github.com	https://github.com/klever-io/klever-go/security/advisories/GHSA-hf2g-6j7h-98wg
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/klever-io/klever-go/security/advisories/GHSA-hf2g-6j7h-98wg

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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          "product": "klever-go",
          "vendor": "klever-io",
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    }
  ],
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GHSA-HF2G-6J7H-98WG

Vulnerability from github – Published: 2026-06-05 16:41 – Updated: 2026-06-09 18:40

Summary

klever-go: Unbounded goroutine spawn on direct-message ingress enables peer-driven DoS

Details

Summary

networkMessenger.directMessageHandler in network/p2p/libp2p/netMessenger.go spawns a fresh goroutine for every incoming direct message before the antiflood layer makes an admission decision. There is no semaphore, throttler, or bound on concurrent in-flight spawns.

A single connected libp2p peer can open a DirectSendID stream and send well-formed TopicMessage envelopes with varying sequence numbers. Each accepted direct message reaches directMessageHandler and triggers a fresh goroutine before processor.ProcessReceivedMessage runs. This allows unbounded goroutine growth and node availability degradation from one peer.

This remains present in the latest release v1.7.17: network/p2p/libp2p/netMessenger.go:1060 still spawns go func(msg p2p.MessageP2P) before processor.ProcessReceivedMessage. I also verified current develop commit 10bcfd50, where the same spawn remains at network/p2p/libp2p/netMessenger.go:1115.

This is distinct from GHSA-74m6-4hjp-7226 and GHSA-87m7-qffr-542v. Those advisories concern MultiDataInterceptor decompression/throttler behavior. This report concerns the libp2p direct-message ingress wrapper spawning an unbounded goroutine before processor-level antiflood/admission logic runs. A patch to Batch.Decompress or MultiDataInterceptor does not bound this direct-message goroutine spawn.

Details

The affected path is network/p2p/libp2p/netMessenger.go in directMessageHandler.

The direct-message path transforms and validates the message, looks up the topic processor, then immediately spawns a goroutine:

func (netMes *networkMessenger) directMessageHandler(message *pubsub.Message, fromConnectedPeer core.PeerID) error {
    var processor p2p.MessageProcessor

    topic := *message.Topic
    msg, err := netMes.transformAndCheckMessage(message, fromConnectedPeer, topic)
    if err != nil {
        return err
    }

    netMes.mutTopics.RLock()
    processor = netMes.processors[topic]
    netMes.mutTopics.RUnlock()

    if processor == nil {
        return fmt.Errorf("%w on directMessageHandler for topic %s", p2p.ErrNilValidator, topic)
    }

    go func(msg p2p.MessageP2P) {
        if check.IfNil(msg) {
            return
        }

        errProcess := processor.ProcessReceivedMessage(msg, fromConnectedPeer)
        // ...
    }(msg)

    return nil
}

The processor-level antiflood decision happens inside ProcessReceivedMessage, after the goroutine, its stack, and the cloned message reference already exist. That means antiflood can bound processing rate, but not goroutine creation rate.

The existing goRoutinesThrottler with capacity broadcastGoRoutines = 1000 is wired into outgoing broadcast paths such as BroadcastOnChannelBlocking, not this incoming direct-message path.

The parallel pubsub ingress path in the same file handles a comparable inbound message surface synchronously:

err = handler.ProcessReceivedMessage(msg, fromConnectedPeer)

So the direct-message path is asymmetric: same transform/check function, same ProcessReceivedMessage callee, but direct-message ingress adds an unbounded goroutine spawn.

Reachability:

directSender.go registers DirectSendID as a libp2p stream protocol.
directStreamHandler reads framed pubsub.Message envelopes from the stream.
directStreamHandler forwards each message to networkMessenger.directMessageHandler.
Any connected peer can send well-formed envelopes to registered topics.
The seenMessages cache keys on From + Seqno; Seqno is attacker-controlled in the envelope, so incrementing it bypasses dedupe.

PoC

GitHub Private Vulnerability Reporting does not appear to allow file attachments in this form, so I am including the reproduction command and captured output inline. I can provide the full Go test file immediately if useful.

The PoC is a Go test file intended to be placed under network/p2p/libp2p/ in a klever-go checkout. It exercises the real network/p2p/libp2p package with NewMockMessenger.

Reproduction:

git clone https://github.com/klever-io/klever-go
cd klever-go
git checkout v1.7.16

# Place dos_directmsg_test.go into:
# network/p2p/libp2p/

go test ./network/p2p/libp2p/ -run TestPoC_ -count=1 -v -timeout 60s

Captured output:

=== RUN   TestPoC_DirectMessageHandler_SpawnsGoroutinePerMessage
    baseline goroutines: 43
    peak goroutines after 500 direct messages: 543 (delta = 500)
    final goroutines after drain + GC: 43
POC_RESULT direct=spawn N=500 baseline=43 peak=543 delta=500 threshold=400 final=43
--- PASS

=== RUN   TestPoC_SynchronousHandler_NoGoroutineGrowth
    baseline goroutines: 47
    peak goroutines after 500 synchronous calls: 47 (delta = 0)
POC_RESULT sync=block N=500 baseline=47 peak=47 delta=0
--- PASS

=== RUN   TestPoC_DirectMessageHandler_NoThrottlerInPath
    all 2000 SendToConnectedPeer calls returned in 2.490708ms -- no throttler blocking
POC_RESULT throttler=absent N=2000 elapsed=2.490708ms
--- PASS

Reading:

500 direct messages with slow processors produced exactly 500 new goroutines.
The synchronous control path produced zero goroutine growth.
2000 messages, twice the outgoing broadcastGoRoutines = 1000 capacity, returned immediately, showing no ingress throttler blocks this path.

Impact

A single connected peer can sustain unbounded goroutine spawn growth on a klever-go node. Each spawned goroutine allocates its own stack, holds message references until the processor returns, and adds scheduler and GC pressure before antiflood admission can reject the message.

Under realistic attacker line rate and non-trivial processor latency, goroutine count can grow faster than the runtime drains it, degrading the node's ability to process legitimate traffic. This maps to the SECURITY.md High category: "Denial of Service affecting network availability."

All testing was local only. I did not contact Klever mainnet, public testnet, hosted RPCs, explorers, or third-party production infrastructure.

Suggested fixes:

Wire goRoutinesThrottler.CanProcess() or a dedicated ingress throttler before the go func() spawn in directMessageHandler.
Or remove the goroutine and call ProcessReceivedMessage synchronously, matching the existing pubsubCallback path.

Disclosure note: I originally sent this report to security@klever.org on 2026-05-13. Since SECURITY.md lists GitHub Private Vulnerability Reporting as the recommended channel, I am resubmitting it here.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.7.17"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/klever-io/klever-go"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.7.14"
            },
            {
              "fixed": "1.7.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-52879"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400",
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-05T16:41:23Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\n`networkMessenger.directMessageHandler` in `network/p2p/libp2p/netMessenger.go` spawns a fresh goroutine for every incoming direct message before the antiflood layer makes an admission decision. There is no semaphore, throttler, or bound on concurrent in-flight spawns.\n\nA single connected libp2p peer can open a `DirectSendID` stream and send well-formed `TopicMessage` envelopes with varying sequence numbers. Each accepted direct message reaches `directMessageHandler` and triggers a fresh goroutine before `processor.ProcessReceivedMessage` runs. This allows unbounded goroutine growth and node availability degradation from one peer.\n\nThis remains present in the latest release `v1.7.17`: `network/p2p/libp2p/netMessenger.go:1060` still spawns `go func(msg p2p.MessageP2P)` before `processor.ProcessReceivedMessage`. I also verified current `develop` commit `10bcfd50`, where the same spawn remains at `network/p2p/libp2p/netMessenger.go:1115`.\n\nThis is distinct from GHSA-74m6-4hjp-7226 and GHSA-87m7-qffr-542v. Those advisories concern `MultiDataInterceptor` decompression/throttler behavior. This report concerns the libp2p direct-message ingress wrapper spawning an unbounded goroutine before processor-level antiflood/admission logic runs. A patch to `Batch.Decompress` or `MultiDataInterceptor` does not bound this direct-message goroutine spawn.\n\n### Details\n\nThe affected path is `network/p2p/libp2p/netMessenger.go` in `directMessageHandler`.\n\nThe direct-message path transforms and validates the message, looks up the topic processor, then immediately spawns a goroutine:\n\n```go\nfunc (netMes *networkMessenger) directMessageHandler(message *pubsub.Message, fromConnectedPeer core.PeerID) error {\n    var processor p2p.MessageProcessor\n\n    topic := *message.Topic\n    msg, err := netMes.transformAndCheckMessage(message, fromConnectedPeer, topic)\n    if err != nil {\n        return err\n    }\n\n    netMes.mutTopics.RLock()\n    processor = netMes.processors[topic]\n    netMes.mutTopics.RUnlock()\n\n    if processor == nil {\n        return fmt.Errorf(\"%w on directMessageHandler for topic %s\", p2p.ErrNilValidator, topic)\n    }\n\n    go func(msg p2p.MessageP2P) {\n        if check.IfNil(msg) {\n            return\n        }\n\n        errProcess := processor.ProcessReceivedMessage(msg, fromConnectedPeer)\n        // ...\n    }(msg)\n\n    return nil\n}\n```\n\nThe processor-level antiflood decision happens inside `ProcessReceivedMessage`, after the goroutine, its stack, and the cloned message reference already exist. That means antiflood can bound processing rate, but not goroutine creation rate.\n\nThe existing `goRoutinesThrottler` with capacity `broadcastGoRoutines = 1000` is wired into outgoing broadcast paths such as `BroadcastOnChannelBlocking`, not this incoming direct-message path.\n\nThe parallel pubsub ingress path in the same file handles a comparable inbound message surface synchronously:\n\n```go\nerr = handler.ProcessReceivedMessage(msg, fromConnectedPeer)\n```\n\nSo the direct-message path is asymmetric: same transform/check function, same `ProcessReceivedMessage` callee, but direct-message ingress adds an unbounded goroutine spawn.\n\nReachability:\n\n- `directSender.go` registers `DirectSendID` as a libp2p stream protocol.\n- `directStreamHandler` reads framed `pubsub.Message` envelopes from the stream.\n- `directStreamHandler` forwards each message to `networkMessenger.directMessageHandler`.\n- Any connected peer can send well-formed envelopes to registered topics.\n- The `seenMessages` cache keys on `From + Seqno`; `Seqno` is attacker-controlled in the envelope, so incrementing it bypasses dedupe.\n\n### PoC\n\nGitHub Private Vulnerability Reporting does not appear to allow file attachments in this form, so I am including the reproduction command and captured output inline. I can provide the full Go test file immediately if useful.\n\nThe PoC is a Go test file intended to be placed under `network/p2p/libp2p/` in a `klever-go` checkout. It exercises the real `network/p2p/libp2p` package with `NewMockMessenger`.\n\nReproduction:\n\n```bash\ngit clone https://github.com/klever-io/klever-go\ncd klever-go\ngit checkout v1.7.16\n\n# Place dos_directmsg_test.go into:\n# network/p2p/libp2p/\n\ngo test ./network/p2p/libp2p/ -run TestPoC_ -count=1 -v -timeout 60s\n```\n\nCaptured output:\n\n```text\n=== RUN   TestPoC_DirectMessageHandler_SpawnsGoroutinePerMessage\n    baseline goroutines: 43\n    peak goroutines after 500 direct messages: 543 (delta = 500)\n    final goroutines after drain + GC: 43\nPOC_RESULT direct=spawn N=500 baseline=43 peak=543 delta=500 threshold=400 final=43\n--- PASS\n\n=== RUN   TestPoC_SynchronousHandler_NoGoroutineGrowth\n    baseline goroutines: 47\n    peak goroutines after 500 synchronous calls: 47 (delta = 0)\nPOC_RESULT sync=block N=500 baseline=47 peak=47 delta=0\n--- PASS\n\n=== RUN   TestPoC_DirectMessageHandler_NoThrottlerInPath\n    all 2000 SendToConnectedPeer calls returned in 2.490708ms -- no throttler blocking\nPOC_RESULT throttler=absent N=2000 elapsed=2.490708ms\n--- PASS\n```\n\nReading:\n\n1. 500 direct messages with slow processors produced exactly 500 new goroutines.\n2. The synchronous control path produced zero goroutine growth.\n3. 2000 messages, twice the outgoing `broadcastGoRoutines = 1000` capacity, returned immediately, showing no ingress throttler blocks this path.\n\n### Impact\n\nA single connected peer can sustain unbounded goroutine spawn growth on a klever-go node. Each spawned goroutine allocates its own stack, holds message references until the processor returns, and adds scheduler and GC pressure before antiflood admission can reject the message.\n\nUnder realistic attacker line rate and non-trivial processor latency, goroutine count can grow faster than the runtime drains it, degrading the node\u0027s ability to process legitimate traffic. This maps to the `SECURITY.md` High category: \"Denial of Service affecting network availability.\"\n\nAll testing was local only. I did not contact Klever mainnet, public testnet, hosted RPCs, explorers, or third-party production infrastructure.\n\nSuggested fixes:\n\n1. Wire `goRoutinesThrottler.CanProcess()` or a dedicated ingress throttler before the `go func()` spawn in `directMessageHandler`.\n2. Or remove the goroutine and call `ProcessReceivedMessage` synchronously, matching the existing `pubsubCallback` path.\n\nDisclosure note: I originally sent this report to `security@klever.org` on 2026-05-13. Since `SECURITY.md` lists GitHub Private Vulnerability Reporting as the recommended channel, I am resubmitting it here.",
  "id": "GHSA-hf2g-6j7h-98wg",
  "modified": "2026-06-09T18:40:40Z",
  "published": "2026-06-05T16:41:23Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/klever-io/klever-go/security/advisories/GHSA-hf2g-6j7h-98wg"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/klever-io/klever-go"
    },
    {
      "type": "WEB",
      "url": "https://github.com/klever-io/klever-go/releases/tag/v1.7.18"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "klever-go: Unbounded goroutine spawn on direct-message ingress enables peer-driven DoS"
}

Sightings

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Nomenclature

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Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Action not permitted

CVE-2026-52879 (GCVE-0-2026-52879)

FKIE_CVE-2026-52879

GHSA-HF2G-6J7H-98WG

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PoC

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