CVE-2022-27191Network attack vector

SSH server crash via unsupported RSA-SHA2 negotiation

Published Mar 18, 2022 · Updated Aug 3, 2024

Denial of service in golang.org/x/crypto/ssh before 0.0.0-20220314234659-1baeb1ce4c0b allows remote attackers to crash SSH servers. The server advertises RSA-SHA2 host-key algorithms solely from PublicKey().Type(), then fails to find a usable key and crashes during negotiation. Exposure requires an ssh-rsa custom Signer passed to ServerConfig.AddHostKey that does not implement AlgorithmSigner; package-provided Signers are unaffected.

CVSS severity7.5
High
EPSS probability3.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in golang.org/x/crypto/ssh before 0.0.0-20220314234659-1baeb1ce4c0b allows remote attackers to crash SSH servers. The server advertises RSA-SHA2 host-key algorithms solely from PublicKey().Type(), then fails to find a usable key and crashes during negotiation. Exposure requires an ssh-rsa custom Signer passed to ServerConfig.AddHostKey that does not implement AlgorithmSigner; package-provided Signers are unaffected.

The record

CVE
CVE-2022-27191
Published
Mar 18, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-327, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 18, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
7.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS: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-327Use of a Broken or Risky Cryptographic Algorithm
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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