CVE-2021-39118Network attack vector

Unauthenticated user enumeration via render endpoint

Published Sep 14, 2021 · Updated Oct 10, 2024

User enumeration in Atlassian Jira Server and Data Center before 8.19.0 allows remote attackers to discover usernames and full names. The /rest/api/1.0/render endpoint returns identifying account data in response to attacker-controlled rendering requests, but Atlassian has not published the exact faulty operation. No authentication or user interaction is required, and the documented consequence is limited to disclosure of account names.

CVSS severity5.3
Medium
EPSS probability1.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

User enumeration in Atlassian Jira Server and Data Center before 8.19.0 allows remote attackers to discover usernames and full names. The /rest/api/1.0/render endpoint returns identifying account data in response to attacker-controlled rendering requests, but Atlassian has not published the exact faulty operation. No authentication or user interaction is required, and the documented consequence is limited to disclosure of account names.

The record

CVE
CVE-2021-39118
Published
Sep 14, 2021
Updated
Oct 10, 2024
Vendor
Atlassian
Product
Jira Server
Classifications
T1589.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Oct 10, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <8.19.0
  2. Affected versionversion=unspecified <8.19.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Atlassian · Jira Serverversion=0 <8.19.0; version=unspecified <8.19.0
Atlassian · Jira Data Centerversion=0 <8.19.0; version=unspecified <8.19.0

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1589.003Gather Victim Identity Information: Employee Names

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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