CVE-2021-31913Network attack vector

Confidentiality loss via unchecked SSO redirect

Published May 11, 2021 · Updated Aug 3, 2024

Open redirect in JetBrains TeamCity before 2020.2.3 allows remote attackers to redirect GitHub SSO token exchanges to untrusted URIs. GitHub SSO redirect_uri validation accepts an attacker-controlled callback destination without confirming that it is an approved URI. Exploitation requires the GitHub SSO flow, and the published record establishes confidentiality loss but does not disclose the exact data exposed.

CVSS severity7.5
High
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in JetBrains TeamCity before 2020.2.3 allows remote attackers to redirect GitHub SSO token exchanges to untrusted URIs. GitHub SSO redirect_uri validation accepts an attacker-controlled callback destination without confirming that it is an approved URI. Exploitation requires the GitHub SSO flow, and the published record establishes confidentiality loss but does not disclose the exact data exposed.

The record

CVE
CVE-2021-31913
Published
May 11, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-601, CWE-354, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
CWE-354Improper Validation of Integrity Check Value
T1528Steal Application Access Token

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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