What’s Vulnerable › Vulnerabilities
CVE-2021-36367
- Severity: high (CVSS 8.1 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.1% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2021-07-09 · updated 2026-06-17
- Weakness: CWE-345
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).
Affected products
- PuTTY: through 0.75
References
- https://git.tartarus.org/?p=simon/putty.git%3Ba=commit%3Bh=1dc5659aa62848f0aeb5de7bd3839fecc7debefa
- https://lists.debian.org/debian-lts-announce/2024/04/msg00016.html
- https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
- https://www.debian.org/security/2023/dsa-5588
- https://git.tartarus.org/?p=simon/putty.git%3Ba=commit%3Bh=1dc5659aa62848f0aeb5de7bd3839fecc7debefa
- https://lists.debian.org/debian-lts-announce/2024/04/msg00016.html
- https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
- https://www.debian.org/security/2023/dsa-5588
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