CVE-2026-55764: klever-io klever-go Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-55764 is a high (CVSS 8.7) Integer Overflow or Wraparound vulnerability in klever-io klever-go. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.4% of scored vulnerabilities.

Timeline

1. 28-08-2026
   PublishedVulnerability first disclosed.
2. 31-08-2026
   Last modifiedVulnerability information updated.

Description

Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.19, Klever-Go allows a mint-role holder to bypass a finite per-nonce MaxSupply on the semi-fungible token add-quantity path. In core/kapp/systemAccount/systemAcount.go, SFTAddCirculation performed meta.Circulation += amount before evaluating whether Circulation exceeded MaxSupply, without checking for signed int64 overflow. A large positive raw Amount supplied through processSemiFungibleAddQuantity in core/kapp/kda/mint.go can wrap Circulation negative, causing the signed maximum-supply comparison to pass and crediting approximately MaxInt64 units while corrupting the on-chain counter. The fungible path is not affected because its MintedValue <= 0 guard detects the overflow. The correction uses the consensus activation flag FixMarketBuyOverflow. This issue is fixed in version 1.7.19.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.