CVE-2022-29245Public exploitNetwork attack vector

SSH communication decryption via predictable X25519 keys

Published May 31, 2022 · Updated Apr 22, 2025

Weak key generation in SSH.NET 2020.0.0 through 2020.0.1 allows attackers to decrypt SSH communications by observing X25519 exchanges. KeyExchangeECCurve25519.Start fills the X25519 client private key with bytes from System.Random, whose default seed derives from the millisecond system tick count. Exploitation requires observation of an X25519 handshake and brute-forcing that seed; the demonstrated consequence is disclosure of the protected SSH session, not modification or interruption.

CVSS severity6.5
Medium
EPSS probability1.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak key generation in SSH.NET 2020.0.0 through 2020.0.1 allows attackers to decrypt SSH communications by observing X25519 exchanges. KeyExchangeECCurve25519.Start fills the X25519 client private key with bytes from System.Random, whose default seed derives from the millisecond system tick count. Exploitation requires observation of an X25519 handshake and brute-forcing that seed; the demonstrated consequence is disclosure of the protected SSH session, not modification or interruption.

The record

CVE
CVE-2022-29245
Published
May 31, 2022
Updated
Apr 22, 2025
Vendor
SSH.NET
Product
SSH.NET
Classifications
CWE-338, CWE-330, T1040
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 31, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 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=>= 2020.0.0, < 2020.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SSH.NET · SSH.NETversion=>= 2020.0.0, < 2020.0.2

Published CVSS scores

6.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:P/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 exploitPublished

Weakness, pattern, technique

CWE-338Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
CWE-330Use of Insufficiently Random Values
T1040Network Sniffing

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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