CVE-2021-20517

Name: CVE-2021-20517
Creator: NVD / NIST
Published: 2021-06-07T14:15:07.767+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.86%

Last modified Jun 17, 2026

CVE-2021-20517 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. IBM WebSphere Application Server Network Deployment 8.5 and 9.0 could allow a remote authenticated attacker to traverse directories. An attacker could send a specially-crafted URL request containing "dot dot" sequences (/../) to read and delete arbitrary files on the system. EPSS estimates a 1.86% chance of exploitation in the next 30 days.

Description

IBM WebSphere Application Server Network Deployment 8.5 and 9.0 could allow a remote authenticated attacker to traverse directories. An attacker could send a specially-crafted URL request containing "dot dot" sequences (/../) to read and delete arbitrary files on the system. IBM X-Force ID: 198435.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

1.86%

76.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-22

Affected Software

Vendor	Product	Versions
Ibm	Websphere Application Server Nd	>= 8.5.0.0, < 8.5.5.20
Ibm	Websphere Application Server Nd	>= 9.0.0.0, < 9.0.5.8

References

https://exchange.xforce.ibmcloud.com/vulnerabilities/198435VDB Entry, Vendor Advisory
https://www.ibm.com/support/pages/node/6456955Patch, Vendor Advisory
https://exchange.xforce.ibmcloud.com/vulnerabilities/198435VDB Entry, Vendor Advisory
https://www.ibm.com/support/pages/node/6456955Patch, Vendor Advisory

Timeline

Published: Jun 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20517?

How severe is CVE-2021-20517?

CVE-2021-20517 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.86% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20517?

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-2021-20517?

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

Scan your code now

Source: NVD / NIST