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CVE Record

CVE-2021-39118: Affected versions of Atlassian Jira Server and Data Center allow remote attackers to discover the usernames...

Affected versions of Atlassian Jira Server and Data Center allow remote attackers to discover the usernames and full names of users via an enumeration vulnerability in the /rest/api/1.0/render endpoint. The affected versions are before version 8.19.0.

MediumCVSS 5.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This CVE lets remote unauthenticated attackers discover Jira user usernames and full names. The business risk is targeted phishing, credential attacks, and reconnaissance against teams using affected self-hosted Jira. It is not described as data modification or service disruption.

Executive priority

Treat this as a moderate-priority information disclosure issue. It should be remediated in normal vulnerability cycles, faster for internet-facing Jira or environments where user identities could support phishing or credential attacks.

Technical view

Affected Atlassian Jira Server and Data Center versions before 8.19.0 expose user identity data through an enumeration issue in the /rest/api/1.0/render endpoint. CVSS 3.1 is 5.3 with network attack vector, low complexity, no privileges, and confidentiality-only impact.

Likely exposure

Exposure is most likely on self-hosted Jira Server or Jira Data Center instances running versions before 8.19.0, especially if reachable from the internet. The provided sources do not list Atlassian Cloud as affected.

Exploitation context

The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector indicates unauthenticated remote reachability, but the documented impact is limited to disclosure of usernames and full names.

Researcher notes

Evidence is clear on affected products, version boundary, endpoint, and impact type. The sources do not provide exploit activity, detailed root cause, or alternate mitigations beyond the fixed version boundary.

Mitigation direction

  • Upgrade Jira Server or Data Center to 8.19.0 or later.
  • Review Atlassian JRASERVER-72736 for vendor remediation details.
  • Prioritize externally reachable Jira instances for remediation.
  • Restrict public access to self-hosted Jira where business requirements allow.
  • Monitor for suspicious enumeration activity against Jira endpoints.

Validation and detection

  • Inventory Jira Server and Data Center versions across all environments.
  • Flag any Jira Server or Data Center instance before 8.19.0.
  • Confirm whether affected instances are internet-accessible.
  • Review application and access logs for unusual requests to the named endpoint.
  • Verify upgraded systems report version 8.19.0 or later.
Prepared
Confidence
high
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-39118 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.3 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.3CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N3.91.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.3Medium
CVSS 3.1 vector shape for CVE-2021-39118Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
AtlassianJira ServerunspecifiedListed
AtlassianJira Data CenterunspecifiedListed
Weakness

CWE details

No CWE listed

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