dbcve.org
Tss LibApplication · Iofinnet

CVE-2023-26557

HIGH · 7.5 CVSS v3.1 Published 2023-04-21
Fix available
A fix is available. Upgrade to 2.0.0 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
io.finnet tss-lib before 2.0.0 can leak the lambda value of a private key via a timing side-channel attack because it relies on Go big.Int, which is not constant time for Cmp, modular exponentiation, or modular inverse. An example leak is in crypto/paillier/paillier.go. (bnb-chain/tss-lib and thorchain/tss are also affected.)

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The tss-lib library (used for threshold signature schemes) uses Go's big.Int for cryptographic operations, which is not constant-time. This allows a timing side-channel attack to leak the lambda value (a private key component) during key generation or signing operations. The vulnerability exists in multiple locations including crypto/paillier/paillier.go.

MitigationUpgrade to tss-lib version 2.0.0 or later which implements constant-time cryptographic operations. If upgrades are not possible, audit all big.Int usage for Cmp, modular exponentiation, and modular inverse operations in cryptographic contexts.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Tss LibApplication
Affected:< 2.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed tss-lib version
    Run 'go list -m all | grep tss-lib' or inspect your go.mod file for the tss-lib version entry
    Affected if The version listed is less than 2.0.0 (e.g., 1.x.x, 0.x.x)
  2. Identify usage of crypto/paillier package
    Search your codebase for imports of 'github.com/ioofinnet/tss-lib/crypto/paillier' or grep for 'paillier' package usage
    Affected if The paillier package from tss-lib is imported and used in your application
  3. Confirm big.Int is used in cryptographic operations
    Inspect the tss-lib crypto/paillier/paillier.go file in your vendor or module cache, looking for big.Int type usage in key generation (KeyGen) or signing (Sign) functions
    Affected if big.Int is used for lambda or other private key component calculations in paillier.go
  4. Determine if key generation or signing is performed
    Review application code to identify if tss-lib key generation (e.g., NewKeyGen, tss.KeyGen) or signing (e.g., NewSign, tss.Sign) functions are called
    Affected if Your application performs TSS key generation or signing operations using the vulnerable tss-lib version

You are affected if your application uses tss-lib version below 2.0.0 and performs key generation or signing operations that involve the paillier package where big.Int handles private key components.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.0.0 or later
Fixed in 2.0.0
Interim mitigation

Upgrade to tss-lib version 2.0.0 or later which implements constant-time cryptographic operations. If upgrades are not possible, audit all big.Int usage for Cmp, modular exponentiation, and modular inverse operations in cryptographic contexts.

Recommended fix High confidence

2.0.0

  1. Identify all direct and indirect dependencies that pull in tss-lib versions before 2.0.0
  2. Update the tss-lib dependency to version 2.0.0 or later in your dependency management file (e.g., go.mod)
  3. Run 'go mod tidy' to update dependencies and remove old versions
  4. Rebuild the application and run existing tests to ensure compatibility
  5. Verify the application functions correctly with the new version
Caveat Review the release notes for 2.0.0 for any API changes before upgrading in production environments

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Tss Lib Scoped from the published advisory
  • Consultation8.0 h
  • Implementation40.0 h
  • Testing16.0 h
  • Review / QA8.0 h
72.0 hours of engineering $12,640
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-26557 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data