High severity · published Jul 9, 2021
CVE-2021-36367
PuTTY through 0.75 proceeds with establishing an SSH session even if it has never sent a substantive authentication response
8.1
CVSS
1.1%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.1% · higher than 66% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PU
Putty · Putty
through 0.75 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-36367
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-36367
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
Release Notes
https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
www.debian.org
https://www.debian.org/security/2023/dsa-5588
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