Vulnerability in Putty
CVE-2021-36367
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).
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.011 (64.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 64.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.chiark.greenend.org.uk/~sgtatham/putty/changes.html (Third Party Advisory, Release Notes)
- git.tartarus.org/
- www.debian.org/security/2023/dsa-5588 (vendor-advisory)
- lists.debian.org/debian-lts-announce/2024/04/msg00016.html (mailing-list)
Frequently asked questions
- What is CVE-2021-36367?
- CVE-2021-36367 is a high-severity vulnerability in Putty, classified under Insufficient Verification of Data Authenticity. CVSS score: 8.1/10. Published 2021-07-09.
- How severe is CVE-2021-36367?
- High severity. CVSS v3 base score is 8.1 out of 10.
- Is CVE-2021-36367 known to be exploited?
- 10 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.