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CVE Record

CVE-2021-37843: The resolution SAML SSO apps for Atlassian products allow a remote attacker to login to a user account when...

The resolution SAML SSO apps for Atlassian products allow a remote attacker to login to a user account when only the username is known (i.e., no other authentication is provided). The fixed versions are for Jira: 3.6.6.1, 4.0.12, 5.0.5; for Confluence 3.6.6, 4.0.12, 5.0.5; for Bitbucket 2.5.9, 3.6.6, 4.0.12, 5.0.5; for Bamboo 2.5.9, 3.6.6, 4.0.12, 5.0.5; and for Fisheye 2.5.9.

CriticalCVSS 9.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

This flaw affects resolution SAML SSO apps for Atlassian products. A remote attacker who knows a username could log in as that user without other authentication. Because Jira, Confluence, Bitbucket, Bamboo, and Fisheye often hold sensitive operational data, vulnerable deployments should be treated as urgent.

Executive priority

Prioritize remediation as critical for any affected Atlassian environment, especially internet-facing systems. Successful exploitation could allow unauthorized access to engineering, documentation, source control, or operational systems without valid credentials.

Technical view

CVE-2021-37843 is an authentication bypass in resolution SAML SSO apps for Atlassian products. The CVSS 3.1 score is 9.8, with network access, low complexity, no privileges, and no user interaction required. Fixed versions are listed separately for Jira, Confluence, Bitbucket, Bamboo, and Fisheye app lines.

Likely exposure

Exposure is likely where organizations run resolution SAML SSO apps on Atlassian Jira, Confluence, Bitbucket, Bamboo, or Fisheye and have not reached the listed fixed versions. Internet-accessible Atlassian portals increase business risk.

Exploitation context

The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The described attack requires only network reachability and a known username, which makes the vulnerability operationally serious even without confirmed exploitation.

Researcher notes

The provided affected CPE data is not specific, so validation should rely on installed resolution SAML SSO app names and versions. Do not assume all Atlassian SSO plugins are affected; the cited advisory concerns resolution SAML SSO apps.

Mitigation direction

  • Identify all resolution SAML SSO apps installed across Atlassian products.
  • Upgrade Jira app versions to 3.6.6.1, 4.0.12, or 5.0.5 as applicable.
  • Upgrade Confluence, Bitbucket, and Bamboo apps to their listed fixed versions.
  • Upgrade Fisheye SAML SSO app to version 2.5.9.
  • Check the vendor advisory for product-specific upgrade guidance.
  • Review recent login activity for suspicious account access.

Validation and detection

  • Confirm each Atlassian product has the resolution SAML SSO app installed or absent.
  • Record installed app versions and compare them with the fixed versions.
  • Verify SAML SSO authentication still works after updating.
  • Review authentication logs for unexpected username-only or abnormal login patterns.
  • Check whether affected portals are reachable from untrusted networks.
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-2021-37843 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AC:L/AV:N/A:H/C:H/I:H/PR:N/S:U/UI: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
9.8CVSS 3.1CriticalCVSS:3.1/AC:L/AV:N/A:H/C:H/I:H/PR:N/S:U/UI:N3.95.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2021-37843Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

CWE details

No CWE listed

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