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0xCERT Security Advisory 0xCERT-2026-0173
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Advisory-ID:  0xCERT-2026-0173
Severity:     High
Published:    2026-09-23T20:17:16.370Z
Updated:      2026-10-08T22:46:36.371Z
Chains:       n/a
URL:          https://www.0xcert.com/advisory/0xCERT-2026-0173

Title: CVE-2026-82405: Klever-Go

Summary
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Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, the KleverUpdateAccountPermission built-in authorizes replacement of a target account's permissions by checking attacker-controlled vmInput.RecipientAddr instead of authenticated vmInput.CallerAddr. An attacker-controlled contract can choose a victim account with configured permissions as RecipientAddr, and contractHasValidPermission can accept the victim's default self-signer as authorization. UpdatePermission can then replace the victim's entire permission set with attacker-supplied Owner permissions, ena…

Details
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Summary
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, the KleverUpdateAccountPermission built-in authorizes replacement of a target account's permissions by checking attacker-controlled vmInput.RecipientAddr instead of authenticated vmInput.CallerAddr. An attacker-controlled contract can choose a victim account with configured permissions as RecipientAddr, and contractHasValidPermission can accept the victim's default self-signer as authorization. UpdatePermission can then replace the victim's entire permission set with attacker-supplied Owner permissions, enabling asset theft or permanent lockout without a victim key or signature. Accounts without stored permissions and the native transaction path are not affected. This issue is fixed in version 1.7.20.

Severity
High (CVSS 8.7), as scored by NVD.

Weakness
- - CWE-863

Recommended actions
- - Check whether you run or depend on the affected component and version
- - Apply the vendor's fix or mitigation from the references below

Source & attribution
This 0xCERT advisory summarises CVE-2026-82405 from the U.S. National Vulnerability Database: https://nvd.nist.gov/vuln/detail/CVE-2026-82405. Details may change; refer to the original source for the authoritative record.

References
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- - https://nvd.nist.gov/vuln/detail/CVE-2026-82405
- - https://gist.github.com/mabdullah22/a41f90aa5ba86bbebf121f739bd5f5e9
- - https://github.com/klever-io/klever-go/commit/c58740eb74d7ee8f07db1e18a7d6214b5559ba32
- - https://github.com/klever-io/klever-go/releases/tag/v1.7.20
- - https://github.com/klever-io/klever-go/security/advisories/GHSA-97cv-x867-6xhm

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