CVE-2026-54755: Klever: Integer overflow in split-royalty validation enables unbounded minting of KLV (native token)

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.6%, percentile 46: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 46% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes github.com/klever-io/klever-go (Go) < 1.7.19, fixed in 1.7.19. Check your lockfile, including transitive dependencies.

What it is

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.

From the GitHub advisory

Summary

The per-entry percentages of a KDA asset's split royalties are validated by summing them into a uint32 accumulator and checking the sum against HundredPercent (10000), with no upper bound on each individual entry. Two split entries whose percentages sum to just over 2^32 wrap around below 10000 and pass validation, while each stored value remains astronomically large (e.g. 0x80000000 = 2,147,483,648 ≈ 21,474,836%).

At royalty payout, each split recipient is credited pool × hugePct / 10000 — far more than the royalty pool — and the resulting negative remainder is silently discarded (if royaltiesToPay

This is independent of, and not mitigated by, the existing FixMarketBuyOverflow guard.

Affected component

Weakness type: CWE-190.

Product: github.com/klever-io/klever-go (Go) · Assigned by: GitHub_M · Published: 2026-08-28

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 0.56% probability of exploitation activity in the next 30 days; percentile 46.

Timeline

• 2026-08-28 — CVE record published by GitHub_M
• 2026-08-28 — GitHub-reviewed advisory GHSA-cgc5-v3f2-8m2v published (critical)
• 2026-08-31 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-cgc5-v3f2-8m2v github.com
2. CVE.org record CVE-2026-54755 cve.org
3. NVD entry CVE-2026-54755 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical Go advisories · Today’s Security Digest