CVE-2025-22869Network attack vector

Denial of service via stalled SSH key exchange

Published Feb 26, 2025 · Updated Apr 11, 2025

Resource exhaustion in golang.org/x/crypto/ssh before 0.35.0 allows remote attackers to interrupt SSH servers via slow key exchange. The handshake transport queues outbound packets without a bound while key exchange is pending, so file-transfer data accumulates instead of being sent. An unauthenticated client can sustain the condition until memory pressure makes the SSH service unresponsive or unavailable.

CVSS severity7.5
High
EPSS probability0.92%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in golang.org/x/crypto/ssh before 0.35.0 allows remote attackers to interrupt SSH servers via slow key exchange. The handshake transport queues outbound packets without a bound while key exchange is pending, so file-transfer data accumulates instead of being sent. An unauthenticated client can sustain the condition until memory pressure makes the SSH service unresponsive or unavailable.

The record

CVE
CVE-2025-22869
Published
Feb 26, 2025
Updated
Apr 11, 2025
Vendor
golang.org/x/crypto
Product
golang.org/x/crypto/ssh
Classifications
CWE-770, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 11, 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 <0.35.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

golang.org/x/crypto · golang.org/x/crypto/sshversion=0 <0.35.0

Published CVSS scores

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

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-770Allocation of Resources Without Limits or Throttling
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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