CVE-2026-49343
MEDIUMCVE-2026-49343 is a medium-severity (CVSS 5.9) Uncontrolled Resource Consumption vulnerability in github.com/klever-io/klever-go. O3 Security confirms whether CVE-2026-49343 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Klever-Go KVM: Throttler slot leak in trie account-data sync causes epoch bootstrap / state sync DoS
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.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-49343.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-49343 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/klever-io/klever-goReal-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
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/klever-io/klever-go | all versions | 1.7.18 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/klever-io/klever-go. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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-2026-49343 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-49343 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-49343. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-49343 in your dependencies?
O3 detects CVE-2026-49343 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.