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Full vulnerability report · 2026
CVE-2026-54755High confidence

Klever-Go: Integer overflow in split-royalty validation enables unbounded minting of KLV (native token)

klever-io · klever-go

Official source article: GitHub GHSA-CGC5-V3F2-8M2V ↗. Check the applicable product and release in the original source.

9.6CriticalCVSS 3.1
Recommended action
Within 7 days

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.56% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs klever-io klever-go and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Open-source package ranges1 source-attributed range

These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.

Ecosystem and packageAffected rangeFirst fixed versionEvidence
gogithub.com/klever-io/klever-go< 1.7.191.7.19GitHub advisory ↗upstream repository advisory · 28 Aug 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-67825

No EUVD known-exploited evidence

Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.19, split-royalty fields decoded in core/kapp/builtInFunctions/utils.go can contain values greater than core.HundredPercent, and core/kapp/kda/create.go and core/kapp/kda/trigger.go sum those values in uint32 accumulators. Crafted values such as two 0x80000000 entries wrap the validation sum to zero and pass CheckValid100Params. Royalty payout paths in core/kapp/accounts/accounts.go, core/kapp/market/market.go, and core/kapp/ito/ito.go then credit each oversized split amount and silently discard a negative remainder, allowing ordinary asset transfers, marketplace purchases, or ITO purchases to create unbacked KLV or other assets. This issue is fixed in version 1.7.19.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
9.6 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.19, split-royalty fields decoded in core/kapp/builtInFunctions/utils.go can contain values greater than core.HundredPercent, and core/kapp/kda/create.go and core/kapp/kda/trigger.go sum those values in uint32 accumulators. Crafted values such as two 0x80000000 entries wrap the validation sum to zero and pass CheckValid100Params. Royalty payout paths in core/kapp/accounts/accounts.go, core/kapp/market/market.go, and core/kapp/ito/ito.go then credit each oversized split amount and silently discard a negative remainder, allowing ordinary asset transfers, marketplace purchases, or ITO purchases to create unbacked KLV or other assets. This issue is fixed in version 1.7.19.

What

Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.19, split-royalty fields decoded in core/kapp/builtInFunctions/utils.go can contain values greater than core.HundredPercent, and core/kapp/kda/create.go and core/kapp/kda/trigger.go sum those values in uint32 accumulators. Crafted values such as two 0x80000000 entries wrap the validation sum to zero and pass CheckValid100Params. Royalty payout paths in core/kapp/accounts/accounts.go, core/kapp/market/market.go, and core/kapp/ito/ito.go then credit each oversized split amount and silently discard a negative remainder, allowing ordinary asset transfers, marketplace purchases, or ITO purchases to create unbacked KLV or other assets. This issue is fixed in version 1.7.19.

Why

The 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.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.19, split-royalty fields decoded in core/kapp/builtInFunctions/utils.go can contain values greater than core.HundredPercent, and core/kapp/kda/create.go and core/kapp/kda/trigger.go sum those values in uint32 accumulators. Crafted values such as two 0x80000000 entries wrap the validation sum to zero and pass CheckValid100Params. Royalty payout paths in core/kapp/accounts/accounts.go, core/kapp/market/market.go, and core/kapp/ito/ito.go then credit each oversized split amount and silently discard a negative remainder, allowing ordinary asset transfers, marketplace purchases, or ITO purchases to create unbacked KLV or other assets. This issue is fixed in version 1.7.19.

Why

The 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.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Integer Overflow or Wraparound → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-190 ↗

CWE-190: Integer Overflow or Wraparound. The 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.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CNoneConfidentiality impact: No direct loss is represented by this metric.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkCWE-190
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-67825Official EUVD mapping

Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.19, split-royalty fields decoded in core/kapp/builtInFunctions/utils.go can contain values greater than core.HundredPercent, and core/kapp/kda/create.go and core/kapp/kda/trigger.go sum those values in uint32 accumulators. Crafted values such as two 0x80000000 entries wrap the validation sum to zero and pass CheckValid100Params. Royalty payout paths in core/kapp/accounts/accounts.go, core/kapp/market/market.go, and core/kapp/ito/ito.go then credit each oversized split amount and silently discard a negative remainder, allowing ordinary asset transfers, marketplace purchases, or ITO purchases to create unbacked KLV or other assets. This issue is fixed in version 1.7.19.

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260902Security Bulletin 2 Sept 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 2 Sept 2026, published on 2 September 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
klever-go: < 1.7.19
Fixed
1.7.19.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 28 Aug 2026 · Last source change 31 Aug 2026, 18:54 UTC · CWE-190 · Integer Overflow or Wraparound

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-29
European sourceENISA EUVD · EUVD-2026-67825
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. ENISA EUVD mappingEUVD-2026-67825 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-67825"}
    ENISA EUVD ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    < 1.7.19 · Fixed: 1.7.19.
    After
    klever-go: < 1.7.19 · Fixed: 1.7.19.
    CNA ↗
  3. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-67825↗CVE authority or vendor reference · GitHub GHSA-CGC5-V3F2-8M2V↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-54755 · cve.blacktree.nl