CVE-2026-58262Public exploitNetwork attack vector

Consensus quorum bypass via counted bitmap padding bits

Published Aug 7, 2026 · Updated Aug 7, 2026

Improper signature verification in Klever klever-go before 1.7.20 allows remote authenticated users to bypass the validator quorum. The verifyConsensusSize method counts every set PubKeysBitmap bit, while the BLS verifier ignores padding positions that map to no validator. Exploitation requires a valid leader signature and one real consensus signature share, allowing attacker-favored blocks to pass without the required two-thirds quorum and weakening finality.

CVSS severity7.1
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in Klever klever-go before 1.7.20 allows remote authenticated users to bypass the validator quorum. The verifyConsensusSize method counts every set PubKeysBitmap bit, while the BLS verifier ignores padding positions that map to no validator. Exploitation requires a valid leader signature and one real consensus signature share, allowing attacker-favored blocks to pass without the required two-thirds quorum and weakening finality.

The record

CVE
CVE-2026-58262
Published
Aug 7, 2026
Updated
Aug 7, 2026
Vendor
Klever
Product
klever-go
Classifications
CWE-347, CWE-345
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.7.20

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Klever · klever-goversion=< 1.7.20

Published CVSS scores

7.1GitHub CNACVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
CWE-345Insufficient Verification of Data Authenticity

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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