CVE-2021-36367

HIGH
Published Jul 9, 20214y ago · Modified Jun 17, 20262w ago
8.1 CVSS 3.1
High
Find Similar
Published Jul 9, 2021 4y ago
Last Modified Jun 17, 2026 2w ago

Description

PuTTY through 0.75 proceeds with establishing an SSH session even if it has never sent a substantive authentication response. This makes it easier for an attacker-controlled SSH server to present a later spoofed authentication prompt (that the attacker can use to capture credential data, and use that data for purposes that are undesired by the client user).

CVSS Details

Base Score
8.1
Exploitability
2.8
Impact
5.2
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Unchanged
Confidentiality High
Integrity High
Availability None

Threat Intelligence

No active exploitation signals — not in CISA KEV and no EPSS score yet.

Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-345

Affected Products 1

VendorProductVersionRange
puttyputty* ≤0.75

References 4

  • git.tartarus.org https://git.tartarus.org/?p=simon/putty.git%3Ba=commit%3Bh=1dc5659aa62848f0aeb5de7bd3839fecc7debefa
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2024/04/msg00016.html
  • chiark.greenend.org.uk https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
    Release NotesThird Party Advisory
  • debian.org https://www.debian.org/security/2023/dsa-5588

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.