klever-go: SFT add-quantity int64 overflow bypasses a finite per-nonce MaxSupply

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-55764: 0.54% estimated exploitation activity in the next 30 days; percentile 45.34 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary On the SFT add-quantity path the only supply bound is SFTAddCirculation, which does meta.Circulation += amount with no overflow guard, then checks if meta.Circulation meta.MaxSupply && meta.MaxSupply != 0. If amount overflows int64 and wraps negative, negative MaxSupply is false, the cap check passes, the function returns nil, and the balance credit stands. A nonce created with a finite MaxSupply (e.g. 1000) can thus be minted to ~MaxInt64 tokens in one transaction. The fungible mint path is not vulnerable — it has a post-increment MintedValue <= 0 guard that the SFT path lacks. Affected code - core/kapp/systemAccount/systemAcount.go:132-138 (SFTAddCirculation, the unguarded +=). - Caller: core/kapp/kda/mint.go:247-283 (processSemiFungibleAddQuantity); contrast guard mint.go:289. Impact A mint-role holder mints ~9.2e18 units of a nonce whose declared MaxSupply is small, with no authorized debit, and corrupts the on-chain Circulation counter to a negative value (misleading any…

Published by the source

28 Aug 2026, 22:08 UTC

Last modified by the source

2 Sep 2026, 19:45 UTC

Source last checked

26 Oct 2026, 15:28 UTC

1. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-mrpp-v6pg-p54x

2. Revision 3 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6330

4. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-mrpp-v6pg-p54x

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# Patch Next advisory brief: CVE-2026-55764

Advisory: klever-go: SFT add-quantity `int64` overflow bypasses a finite per-nonce MaxSupply
IDs: CVE-2026-55764, GHSA-mrpp-v6pg-p54x
Record: https://patchnext.com/advisories/cve-2026-55764 (revision 4, source checked 26 Oct 2026, 15:28 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/klever-io/klever-go 1.7.19. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/klever-io/klever-go: affected < 1.7.19; fixed in 1.7.19

## Suggested inspection (read-only)
- Go github.com/klever-io/klever-go: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/klever-io/klever-go.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-mrpp-v6pg-p54x (OSV record GHSA-mrpp-v6pg-p54x lists affected ranges: Go github.com/klever-io/klever-go >=0 <1.7.19 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6330 (OSV record GO-2026-6330 lists affected ranges: Go github.com/klever-io/klever-go >=0 <1.7.19 (fixed))
- Verified: https://github.com/advisories/GHSA-mrpp-v6pg-p54x (GitHub-reviewed advisory GHSA-mrpp-v6pg-p54x lists affected ranges: Go github.com/klever-io/klever-go >=0 <1.7.19)

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