CVE-2021-39121Network attack vector

Authenticated private-project key enumeration via validation endpoint

Published Sep 8, 2021 · Updated Oct 10, 2024

Information disclosure in Jira Server and Data Center before 8.5.18 allows remote authenticated users to enumerate private project keys. The /rest/api/latest/projectvalidate/key endpoint returns distinguishable validation results for attacker-supplied candidate keys, enabling repeated guesses to reveal private-project identifiers. A valid Jira account is required; affected releases also include 8.6.0 through 8.13.9 and 8.14.0 through 8.18.1, and only project identifiers are exposed.

CVSS severity4.3
Medium
EPSS probability1.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Jira Server and Data Center before 8.5.18 allows remote authenticated users to enumerate private project keys. The /rest/api/latest/projectvalidate/key endpoint returns distinguishable validation results for attacker-supplied candidate keys, enabling repeated guesses to reveal private-project identifiers. A valid Jira account is required; affected releases also include 8.6.0 through 8.13.9 and 8.14.0 through 8.18.1, and only project identifiers are exposed.

The record

CVE
CVE-2021-39121
Published
Sep 8, 2021
Updated
Oct 10, 2024
Vendor
Atlassian
Product
Jira Server
Classifications
T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 8, 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=8.14.0 <unspecified
  2. Affected versionversion=8.6.0 <unspecified
  3. Affected versionversion=unspecified <8.13.10
  4. Affected versionversion=unspecified <8.18.2
  5. Affected versionversion=unspecified <8.5.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Atlassian · Jira Serverversion=8.14.0 <unspecified; version=8.6.0 <unspecified; version=unspecified <8.13.10; version=unspecified <8.18.2; version=unspecified <8.5.18
Atlassian · Jira Data Centerversion=8.14.0 <unspecified; version=8.6.0 <unspecified; version=unspecified <8.13.10; version=unspecified <8.18.2; version=unspecified <8.5.18

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
4.0NIST NVDAV:N/AC:L/Au:S/C:P/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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1213Data from Information Repositories

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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