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CVE-2021-36367

HIGHCVSS 8.1/10EPSS 1.11%

Last modified

CVE-2021-36367 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. 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).. EPSS estimates a 1.11% chance of exploitation in the next 30 days.

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).

Metrics

CVSS 3.1
8.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS Probability
1.11%

61.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
PuttyPutty<= 0.75

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is 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).
How severe is CVE-2021-36367?
CVE-2021-36367 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 1.11% probability of exploitation in the next 30 days.
How do I fix CVE-2021-36367?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-36367?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST