CVE-2021-37843

9.8 CRITICAL 2% exploit odds No fix listed Auth & access Web app

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 1.5% chance of exploitation in the next 30 days (EPSS).
Fix: No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

2021-08-02 00:00 UTC ReservedThe CVE id was reserved by its CNA
2021-08-02 19:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 04:01 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 1.5% in the next 30 days (EPSS).
Severity: 9.8 CRITICAL (CVSS).
Fix: none linked yet, which raises it.

Details

Published: 2021-08-02 19:15 UTC
Last modified: 2026-06-17 04:01 UTC
Exploit probability: 1.5% · EPSS, next 30 days
Weakness: CWE-306 · Missing authentication
Record status: Modified

Affected

Atlassian Saml Single Sign On < 2.5.9
Atlassian Saml Single Sign On < 3.5.6
Atlassian Saml Single Sign On < 3.6.6.1
Atlassian Saml Single Sign On < 3.6.6
Atlassian Saml Single Sign On < 4.0.12
Atlassian Saml Single Sign On < 5.0.5

Attack profile CVSS 3.1 · 9.8

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

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

Is it in your code?

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References

NVD record · CVE.org record