CVE-2023-26557: io.finnet tss-lib before 2.0.0 can leak the lambda value of a private key via a timing side-channel attack bec

Q: How do I fix CVE-2023-26557?

tss-lib: upgrade to 2.0.0. Exact commands for each OS are on this page.

Q: Is CVE-2023-26557 being exploited?

CVE-2023-26557 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-26557 affect?

CVE-2023-26557 affects tss-lib. Severity is high (CVSS 7.5). 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 i

Q: How urgent is CVE-2023-26557?

Priority 46/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADE

CVE-2023-26557 is a high-severity flaw (CVSS 7.5) affecting tss-lib. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.)

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.9% (top 41%)
CISA exploited list	No
Weakness	CWE-203
Published	2023-04-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: iofinnet

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-04-21 18:15 UTCPublished CVE record published
2026-06-17 05:43 UTCUpdated Record last modified

iofinnet tss-lib UPGRADE

Affected: < 2.0.0

Fixed in: 2.0.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy tss-lib || rpm -q tss-lib || tss-lib --version

2. UPGRADE to 2.0.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tss-lib

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tss-lib

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-26557?

tss-lib: upgrade to 2.0.0. Exact commands for each OS are on this page.

Is CVE-2023-26557 being exploited?

CVE-2023-26557 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-26557 affect?

CVE-2023-26557 affects tss-lib. Severity is high (CVSS 7.5). 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 i

How urgent is CVE-2023-26557?

Priority 46/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2023-26556 CRITICAL 9.1 UPGRADE io.finnet tss-lib before 2.0.0 can leak a secret key via a timing side-channel attack because it relies on the
CVE-2022-47931 CRITICAL 9.1 UPGRADE IO FinNet tss-lib before 2.0.0 allows a collision of hash values.
CVE-2022-47930 MEDIUM 6.8 UPGRADE An issue was discovered in IO FinNet tss-lib before 2.0.0

References

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