CVE-2021-26081

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-07-20 · updated 2026-06-17

Description

REST API in Atlassian Jira Server and Jira Data Center before version 8.5.14, from version 8.6.0 before 8.13.6, and from version 8.14.0 before 8.16.1 allows remote attackers to enumerate usernames via a Sensitive Data Exposure vulnerability in the `/rest/api/latest/user/avatar/temporary` endpoint.

Affected products

Atlassian Data Center: before 8.5.14 — fixed in 8.5.14
Atlassian Jira: before 8.5.14 — fixed in 8.5.14
Atlassian Jira: from 8.6.0 before 8.13.6; from 8.14.0 before 8.16.1 — fixed in 8.13.6, 8.16.1
Atlassian Jira: from 8.6.0 before 8.13.6; from 8.14.0 before 8.16.1 — fixed in 8.13.6, 8.16.1

How to fix

Upgrade to a fixed version: Atlassian Data Center 8.5.14; Atlassian Jira 8.5.14; Atlassian Jira 8.13.6, 8.16.1; Atlassian Jira 8.13.6, 8.16.1. Check the vendor advisory for mitigations.

References

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