CVE-2023-26557 — tss-lib
HIGHCVE-2023-26557 is a high-severity (CVSS 7.5) CWE-203 vulnerability in github.com/bnb-chain/tss-lib. A fix is available for github.com/bnb-chain/tss-lib — see the affected versions and patch details below.
IO FinNet tss-lib vulnerable to timing attack from non-constant time scalar arithmetic
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-26557.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-26557 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/bnb-chain/tss-lib🐹github.com/binance-chain/tss-libReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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.)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/bnb-chain/tss-lib | all versions | 1.3.6-0.20230324145555-bb6fb30bd3ebgo get github.com/bnb-chain/tss-lib@v1.3.6-0.20230324145555-bb6fb30bd3eb |
| 🐹Go | github.com/binance-chain/tss-lib | all versions | 1.3.6-0.20230324145555-bb6fb30bd3ebgo get github.com/binance-chain/tss-lib@v1.3.6-0.20230324145555-bb6fb30bd3eb |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/bnb-chain/tss-lib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/bnb-chain/tss-lib to 1.3.6-0.20230324145555-bb6fb30bd3eb or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-26557 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-26557 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-26557. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-26557 in your dependencies?
O3 Security finds CVE-2023-26557 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.