CVE-2026-55764 Klever-Go: SFT add-quantity `int64` overflow bypasses a finite per-nonce MaxSupply
A mint-role holder can exploit an integer overflow to bypass supply limits and mint excessive tokens, corrupting the blockchain state.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55764?
CVE-2026-55764 is a high-severity vulnerability in klever-io klever-go, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-190
Which versions are affected by CVE-2026-55764?
3 open source packages ship an affected version, including github.com/klever-io/klever-go.
| Package | Affected | Fixed in |
|---|---|---|
github.com/klever-io/klever-go Go | All versions | 1.7.19 |
github.com/klever-io/klever-go Go | All versions | 1.7.19 |
github.com/klever-io/klever-go Go | All versions | 1.7.19 |
How do I fix CVE-2026-55764?
Upgrade github.com/klever-io/klever-go to 1.7.19 or later.
Is CVE-2026-55764 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55764 exists.
Sources
Also known as GHSA-mrpp-v6pg-p54x, GO-2026-6330.