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Jira ServerApplication · Atlassian

CVE-2021-43942

MEDIUM · 6.1 CVSS v3.1 Published 2022-01-04
Fix available
A fix is available. Upgrade to 8.13.5 / 8.20.3 or later.
See remediation →
68/100
Remediation priority · Elevated
High EPSS Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Affected versions of Atlassian Jira Server and Data Center allow remote attackers to inject arbitrary HTML or JavaScript via a Reflected Cross-Site Scripting (XSS) vulnerability in the /rest/collectors/1.0/template/custom endpoint. To exploit this issue, the attacker must trick a user into visiting a malicious website. The affected versions are before version 8.13.15, and from version 8.14.0 before 8.20.3.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is a reflected Cross-Site Scripting (XSS) vulnerability in Atlassian Jira Server and Data Center's /rest/collectors/1.0/template/custom endpoint. Attackers can inject arbitrary HTML or JavaScript by tricking users into visiting malicious websites that redirect to the vulnerable Jira endpoint with crafted parameters.

MitigationUpgrade Jira to version 8.13.15 or 8.20.3 or later to remediate this vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Jira ServerApplication
Affected:>= 8.14.0, < 8.20.3
Jira Server And Data CenterApplication
Affected:< 8.13.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed Jira version
    Log into Jira as administrator, click the gear icon > Applications > Jira software. The version is displayed on the right side under 'Jira software' heading. Alternatively, access the /rest/api/2/serverInfo endpoint to retrieve version programmatically.
    Affected if The version number falls within the ranges: 8.14.0 through 8.20.2 (inclusive) for Jira Server, OR any version below 8.13.5 for Jira Server and Data Center.
  2. Confirm Jira deployment type
    Verify whether your deployment is Jira Server (self-hosted standalone) or Jira Data Center (clustered deployment). Check your installation documentation or the /rest/api/2/serverInfo response field 'deploymentType'.
    Affected if Running Jira Server or Data Center versions 8.14.0 to < 8.20.3, or Jira Server and Data Center < 8.13.5.
  3. Verify the Issue Collector REST endpoint is accessible
    Attempt to access /rest/collectors/1.0/template/custom?foo=bar in a browser or via curl. The endpoint typically responds with JSON even without authentication.
    Affected if The endpoint returns a valid HTTP response (status 200). This indicates the vulnerable endpoint is exposed, though exploitation still requires crafting malicious URL parameters.
  4. Review access logs for suspicious collector endpoint requests
    Search your Jira access logs (typically in <jira-home>/logs/atlassian-jira-access-log.log) for requests to /rest/collectors/1.0/template/custom containing unusual characters like <script>, javascript:, or other HTML/JS tags in URL parameters.
    Affected if Log entries show requests to the collector endpoint with potential XSS payload patterns in query parameters.

Your environment is affected if Jira Server or Data Center version is 8.14.0 through 8.20.2, or any version below 8.13.5.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 8.13.5 / 8.20.3 or later
Fixed in 8.13.58.20.3
Interim mitigation

Upgrade Jira to version 8.13.15 or 8.20.3 or later to remediate this vulnerability.

Recommended fix High confidence

Jira Server/Data Center 8.13.15+ or 8.20.3+ (depending on current version branch)

  1. 1. Identify the current Jira Server or Data Center version from the Atlassian Administration console
  2. 2. If the current version is 8.13.x and less than 8.13.15, plan an upgrade to version 8.13.15 or later (e.g., 8.13.15, 8.13.16, etc.)
  3. 3. If the current version is 8.14.0 through 8.20.2, plan an upgrade to version 8.20.3 or later (e.g., 8.20.3, 8.20.4, 8.21.x, etc.)
  4. 4. Review the Jira upgrade guide at https://confluence.atlassian.com/jira/upgrade-158915062.html for pre-upgrade checklist items
  5. 5. Create a full backup of the Jira database and home directory before upgrading
  6. 6. Download the target fixed version from https://www.atlassian.com/software/jira/download
  7. 7. Perform the upgrade following Atlassian's standard upgrade procedure
  8. 8. After upgrade, verify the /rest/collectors/1.0/template/custom endpoint is no longer vulnerable
Caveat Review Atlassian's upgrade notes for potential configuration or compatibility changes between your current version and the target version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Jira Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-43942 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data