# CVE-2026-82405: Klever-Go account takeover via authorization bypass in UpdateAccountPermission Source: https://junglewise.ai/threats/cve-2026-82405-klever-go-account-takeover-via-authorization-bypass-in Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats Published: 2026-09-23. Updated: 2026-09-25 License: CC BY 4.0 with a link back CVE-2026-82405 · Severity: high · CVSS 4 · Published 2026-09-23 Klever-Go is a blockchain virtual machine framework. A critical authorization flaw in the UpdateAccountPermission built-in function allows an attacker to completely take over any account with configured permissions by deploying a malicious smart contract. After takeover, the attacker gains full control of the victim's assets and operations without requiring any of the victim's cryptographic keys. Technologies: [github.com/klever-io/klever-go (Go)](https://junglewise.ai/threats/technologies/github-com-klever-io-klever-go). Vendors: [Go](https://junglewise.ai/threats/vendors/go). ## Quick answers **Is CVE-2026-82405 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-82405 being exploited in the wild. **How severe is CVE-2026-82405?** High severity, with a CVSS score of 4, published 23 September 2026. **Which products and versions are affected?** github.com/klever-io/klever-go (Go) <= 1.7.19, SEMVER:introduced=0,fixed=1.7.20. **Is there a fix for CVE-2026-82405?** Yes. github.com/klever-io/klever-go (Go): upgrade to 1.7.20 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve. **How is CVE-2026-82405 attacked?** It is attacked over the network, in a software library. **Am I affected by CVE-2026-82405?** Check whether you run github.com/klever-io/klever-go (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you. ## How to fix - github.com/klever-io/klever-go (Go): upgrade to 1.7.20 or later ```sh go get github.com/klever-io/klever-go@v1.7.20 ``` ## Technical details The vulnerability is an authorization bypass in the KleverUpdateAccountPermission handler (kleverUpdateAccountPermission.go). The flaw occurs because the authorization check uses vmInput.RecipientAddr (attacker-controlled) instead of vmInput.CallerAddr (authenticated). When a contract calls the built-in via ExecuteOnDestContext, RecipientAddr can be set to any target account; the handler then verifies whether RecipientAddr is an authorized signer on the *target* account's permission set. Since every account with configured permissions lists itself as an Owner signer by default, this check always passes when RecipientAddr equals the target. An attacker can invoke this by deploying a contract that calls UpdateAccountPermission with the victim's account address as RecipientAddr and attacker-supplied signers as the new permission set. No signature or key from the victim is required. The native transaction path (txProcess.go) is safe as it uses tx.GetSender(). A proof-of-concept confirms full permission rewrite affecting every multisig or advanced-permission account. ## Affected products - Klever Klever-Go