CVE-2024-23342Public exploitNetwork attack vector

Private-key recovery via nonce-dependent signature timing

Published Jan 22, 2024 · Updated May 30, 2025

Timing side channel in tlsfuzzer python-ecdsa 0.18.0 and earlier allows attackers to recover P-256 private keys from signatures. SigningKey.sign_digest() performs scalar multiplication with nonce-dependent timing, exposing the nonce bit length across repeated signatures. Exploitation requires timing hundreds to thousands of signing operations on known messages; signature verification is unaffected.

CVSS severity7.4
High
EPSS probability0.98%
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 tlsfuzzer python-ecdsa 0.18.0 and earlier allows attackers to recover P-256 private keys from signatures. SigningKey.sign_digest() performs scalar multiplication with nonce-dependent timing, exposing the nonce bit length across repeated signatures. Exploitation requires timing hundreds to thousands of signing operations on known messages; signature verification is unaffected.

The record

CVE
CVE-2024-23342
Published
Jan 22, 2024
Updated
May 30, 2025
Vendor
tlsfuzzer
Product
python-ecdsa
Classifications
CWE-203, CWE-385, CWE-208
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 22, 2024CVE publishedPublication date reported by the CVE source.
  2. May 30, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 0.18.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

tlsfuzzer · python-ecdsaversion=<= 0.18.0

Published CVSS scores

7.4GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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 exploitPublished

Weakness, pattern, technique

CWE-203Observable Discrepancy
CWE-385Covert Timing Channel
CWE-208Observable Timing Discrepancy

Public exploit references

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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