CVE-2023-26556

Name: CVE-2023-26556
Creator: NVD / NIST
Published: 2023-04-21T18:15:07.927+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 0.86%

Last modified Jun 17, 2026

CVE-2023-26556 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. io.finnet tss-lib before 2.0.0 can leak a secret key via a timing side-channel attack because it relies on the scalar-multiplication implementation in Go crypto/elliptic, which is not constant time (there is an if statement in a loop). One leak is in ecdsa/keygen/round_2.go. EPSS estimates a 0.86% chance of exploitation in the next 30 days.

Description

io.finnet tss-lib before 2.0.0 can leak a secret key via a timing side-channel attack because it relies on the scalar-multiplication implementation in Go crypto/elliptic, which is not constant time (there is an if statement in a loop). One leak is in ecdsa/keygen/round_2.go. (bnb-chain/tss-lib and thorchain/tss are also affected.)

Metrics

CVSS 3.1

9.1/10

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

EPSS Probability

0.86%

54.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Iofinnet	Tss-Lib	< 2.0.0

References

Timeline

Published: Apr 21, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-26556?

How severe is CVE-2023-26556?

CVE-2023-26556 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.86% probability of exploitation in the next 30 days.

How do I fix CVE-2023-26556?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-26556?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST