CVE-2026-40070Public exploitNetwork attack vector

Credential forgery via unverified certifier signatures

Published Apr 9, 2026 · Updated Apr 9, 2026

Improper signature verification in BSV Ruby SDK before 0.8.2 and bsv-wallet before 0.3.4 allows attackers to forge identity certificates. WalletClient#acquire_certificate writes caller- or endpoint-supplied signatures to storage without checking them against the claimed certifier's key. Reachability requires access to the acquisition API or control of its issuance endpoint; stored forgeries are trusted by list_certificates and prove_certificate.

CVSS severity8.1
High
EPSS probability0.14%
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 BSV Ruby SDK before 0.8.2 and bsv-wallet before 0.3.4 allows attackers to forge identity certificates. WalletClient#acquire_certificate writes caller- or endpoint-supplied signatures to storage without checking them against the claimed certifier's key. Reachability requires access to the acquisition API or control of its issuance endpoint; stored forgeries are trusted by list_certificates and prove_certificate.

The record

CVE
CVE-2026-40070
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
BSV Blockchain
Product
BSV Ruby SDK
Classifications
CWE-347, T1649
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 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=>= 0.3.1, < 0.8.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

BSV Blockchain · BSV Ruby SDKversion=>= 0.3.1, < 0.8.2
BSV Blockchain · bsv-sdkversion=>= 0.3.1, < 0.8.2
BSV Blockchain · bsv-walletversion=>= 0.1.2, < 0.3.4

Published CVSS scores

8.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
T1649Steal or Forge Authentication Certificates

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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