CVE-2026-40070 bsv-sdk and bsv-wallet persist unverified certifier signatures in acquire_certificate (direct and issuance paths)
Attackers can forge identity certificates in the BSV Ruby SDK by bypassing signature verification, leading to fraudulent certificate storage and validation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40070?
CVE-2026-40070 is a high-severity vulnerability in sgbett bsv-ruby-sdk, published on 9 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
BSV Ruby SDK is the Ruby SDK for the BSV blockchain. From 0.3.1 to before 0.8.2, BSV::Wallet::WalletClient#acquire_certificate persists certificate records to storage without verifying the certifier's signature over the certificate contents. In acquisition_protocol: 'direct', the caller supplies all certificate fields (including signature:) and the record is written to storage verbatim. In acquisition_protocol: 'issuance', the client POSTs to a certifier URL and writes whatever signature the response body contains, also without verification. An attacker who can reach either API (or who controls a certifier endpoint targeted by the issuance path) can forge identity certificates that subsequently appear authentic to list_certificates and prove_certificate.
Weakness: CWE-347
Which versions are affected by CVE-2026-40070?
4 open source packages ship an affected version, including bsv-sdk and bsv-wallet. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
bsv-sdk RubyGems | From 0.3.1 | 0.8.2 |
bsv-sdk RubyGems | From 0.3.1 | 0.8.2 |
bsv-wallet RubyGems | From 0.1.2 | 0.3.4 |
bsv-wallet RubyGems | From 0.1.2 | 0.3.4 |
Products include Sgbett Bsv-Wallet, Sgbett Bsv Ruby Sdk.
How do I fix CVE-2026-40070?
Upgrade bsv-sdk to 0.8.2 or later.
Is CVE-2026-40070 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40070 exists.
Sources
Also known as GHSA-hc36-c89j-5f4j.