Klever-Go KVM: Throttler slot leak in trie account-data sync causes epoch bootstrap / state sync DoS

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-49343: 0.41% estimated exploitation activity in the next 30 days; percentile 35.53 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The account-data trie syncers leak bounded throttler slots on error paths in syncDataTrie(). Each failed trie sync permanently consumes one slot from the NumGoRoutinesThrottler, and the slot is never returned unless the sync succeeds or the root hash was already present. I confirmed this on the current default branch develop at commit 9640d63 (observed on May 20, 2026). I also confirmed the bug with a runtime PoC using the real timeout path in trieSyncer.StartSyncing(): two timed-out sync attempts are enough to exhaust a throttler with capacity 2. This affects the epoch bootstrap path because syncUserAccountsState() and syncKappAccountsState() create bounded throttlers and abort bootstrap immediately if the syncer returns an error. Once enough trie-root sync attempts fail, the syncer cannot make forward progress and bootstrap fails.

Affected Components - data/syncer/userAccountsSyncer.go - data/syncer/kappAccountsSyncer.go - data/trie/sync.go -…

Published by the source

5 Jun 2026, 16:40 UTC

Last modified by the source

5 Jun 2026, 16:40 UTC

Source last checked

26 Oct 2026, 15:23 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fw38-pc54-jvx9

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# Patch Next advisory brief: CVE-2026-49343

Advisory: Klever-Go KVM: Throttler slot leak in trie account-data sync causes epoch bootstrap / state sync DoS
IDs: CVE-2026-49343, GHSA-fw38-pc54-jvx9
Record: https://patchnext.com/advisories/cve-2026-49343 (revision 1, source checked 26 Oct 2026, 15:23 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/klever-io/klever-go 1.7.18. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/klever-io/klever-go: affected < 1.7.18; fixed in 1.7.18

## Suggested inspection (read-only)
- Go github.com/klever-io/klever-go: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/klever-io/klever-go.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-fw38-pc54-jvx9 (GitHub-reviewed advisory GHSA-fw38-pc54-jvx9 lists affected ranges: Go github.com/klever-io/klever-go >=0 <1.7.18)

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