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CVE Record

CVE-2021-39123: Affected versions of Atlassian Jira Server and Data Center allow unauthenticated remote attackers to impact...

Affected versions of Atlassian Jira Server and Data Center allow unauthenticated remote attackers to impact the application's availability via a Denial of Service (DoS) vulnerability in the /rest/gadget/1.0/createdVsResolved/generate endpoint. The affected versions are before version 8.16.0.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This vulnerability lets an unauthenticated remote attacker degrade or stop Jira service availability through a specific Jira gadget endpoint. It affects Atlassian Jira Server and Jira Data Center versions before 8.16.0. The business impact is downtime, not data theft or tampering based on the supplied CVSS vector.

Executive priority

Treat this as a high-priority availability issue for business-critical Jira systems. Schedule upgrade work promptly, especially for internet-facing or widely accessible instances, but avoid overstating breach risk because sources only support denial of service.

Technical view

CVE-2021-39123 is a network-reachable denial-of-service flaw in /rest/gadget/1.0/createdVsResolved/generate. CVSS 3.1 is 7.5: low complexity, no privileges, no user interaction, unchanged scope, and high availability impact only. Sources identify Jira Server and Jira Data Center before 8.16.0 as affected.

Likely exposure

Exposure is likely where Jira Server or Jira Data Center earlier than 8.16.0 is reachable by untrusted networks or the internet. Internal-only deployments still have risk from unauthenticated users who can reach the application.

Exploitation context

The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The risk remains material because exploitation is described as unauthenticated, remote, low complexity, and availability-impacting.

Researcher notes

No CWE is provided in the source bundle. Public details identify the affected endpoint and version boundary but not root cause, exploit mechanics, or vendor workarounds beyond the fixed version threshold. Avoid inferring confidentiality or integrity impact.

Mitigation direction

  • Identify all Jira Server and Data Center deployments and record exact versions.
  • Upgrade affected Jira Server or Data Center instances to 8.16.0 or later.
  • Review Atlassian issue JRASERVER-72237 for vendor-specific guidance.
  • Reduce untrusted network access to Jira while remediation is pending.
  • Monitor Jira availability and error patterns during the remediation window.

Validation and detection

  • Confirm each Jira Server and Data Center instance is version 8.16.0 or later.
  • Verify no vulnerable Jira instances are exposed to untrusted networks.
  • Review web access logs for unusual requests to the named gadget endpoint.
  • Confirm vulnerability scanners no longer flag CVE-2021-39123.
  • Document remediation status for each Jira environment.
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-2021-39123 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
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

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

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
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2021-39123Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.