CVE-2023-26557Network attack vector

Private-key disclosure via variable-time big-integer arithmetic

Published Apr 21, 2023 · Updated Feb 5, 2025

Timing side channel in io.finnet tss-lib before 2.0.0 allows remote attackers to recover private-key lambda values. The Paillier code in crypto/paillier/paillier.go uses Go big.Int comparison, exponentiation, and inverse operations whose runtimes vary with secret-dependent values. Exploitation requires repeated timing observations of cryptographic operations; recovered lambda values expose private-key material without directly modifying data or interrupting service.

CVSS severity7.5
High
EPSS probability0.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Timing side channel in io.finnet tss-lib before 2.0.0 allows remote attackers to recover private-key lambda values. The Paillier code in crypto/paillier/paillier.go uses Go big.Int comparison, exponentiation, and inverse operations whose runtimes vary with secret-dependent values. Exploitation requires repeated timing observations of cryptographic operations; recovered lambda values expose private-key material without directly modifying data or interrupting service.

The record

CVE
CVE-2023-26557
Published
Apr 21, 2023
Updated
Feb 5, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-203Observable Discrepancy

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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