CVE-2021-31520

Name: CVE-2021-31520
Creator: NVD / NIST
Published: 2021-05-10T11:15:08.003+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 3.90%

Last modified Jun 17, 2026

CVE-2021-31520 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. A weak session token authentication bypass vulnerability in Trend Micro IM Security 1.6 and 1.6.5 could allow an remote attacker to guess currently logged-in administrators' session session token in order to gain access to the product's web management interface.. EPSS estimates a 3.90% chance of exploitation in the next 30 days.

Description

A weak session token authentication bypass vulnerability in Trend Micro IM Security 1.6 and 1.6.5 could allow an remote attacker to guess currently logged-in administrators' session session token in order to gain access to the product's web management interface.

Metrics

CVSS 3.1

8.1/10

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

EPSS Probability

3.90%

88.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

Affected Software

Vendor	Product	Versions
Trendmicro	Im Security	1.6
Trendmicro	Im Security	1.6.5

References

https://success.trendmicro.com/solution/000286439Patch, Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-525/Third Party Advisory, VDB Entry
https://success.trendmicro.com/solution/000286439Patch, Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-525/Third Party Advisory, VDB Entry

Timeline

Published: May 10, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-31520?

How severe is CVE-2021-31520?

CVE-2021-31520 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 3.90% probability of exploitation in the next 30 days.

How do I fix CVE-2021-31520?

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-2021-31520?

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

Scan your code now

Source: NVD / NIST