CVE-2026-44405

SSH authentication integrity reduction via SHA-1 RSA signatures

Published May 5, 2026 · Updated May 6, 2026

Cryptographic weakness in Paramiko through 4.0.0 before a448945 allows attackers to reduce SSH authentication integrity. RSAKey.HASHES maps the ssh-rsa and certificate identifiers to SHA-1, causing sign_ssh_data and verify_ssh_sig to create or accept deprecated signatures. The attacker must occupy an adjacent network position during SSH authentication, and the published consequence is limited to integrity.

CVSS severity3.4
Low
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic weakness in Paramiko through 4.0.0 before a448945 allows attackers to reduce SSH authentication integrity. RSAKey.HASHES maps the ssh-rsa and certificate identifiers to SHA-1, causing sign_ssh_data and verify_ssh_sig to create or accept deprecated signatures. The attacker must occupy an adjacent network position during SSH authentication, and the published consequence is limited to integrity.

The record

CVE
CVE-2026-44405
Published
May 5, 2026
Updated
May 6, 2026
Vendor
Paramiko
Product
Paramiko
Classifications
CWE-327, T1557
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 5, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 2026Record 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 <a4489456b6f65281e172380cc4826cee5e851dbb

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Paramiko · Paramikoversion=0 <a4489456b6f65281e172380cc4826cee5e851dbb

Published CVSS scores

3.4MITRECVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:N/I:L/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
T1557Adversary-in-the-Middle

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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