CVE-2021-37156Network attack vector

Account access persistence via unexpired sessions

Published Aug 5, 2021 · Updated Aug 4, 2024

Insufficient session expiration in Redmine 4.2.0 and 4.2.1 allows remote attackers with a valid session to keep account access after 2FA activation. The 2FA setup path leaves concurrent sessions, autologin tokens, and recovery codes active instead of resetting them. Exploitation requires control of a session established before 2FA is enabled and preserves that session's existing account permissions.

CVSS severity7.5
High
EPSS probability1.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient session expiration in Redmine 4.2.0 and 4.2.1 allows remote attackers with a valid session to keep account access after 2FA activation. The 2FA setup path leaves concurrent sessions, autologin tokens, and recovery codes active instead of resetting them. Exploitation requires control of a session established before 2FA is enabled and preserves that session's existing account permissions.

The record

CVE
CVE-2021-37156
Published
Aug 5, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-613, T1550.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-613Insufficient Session Expiration
T1550.004Use Alternate Authentication Material: Web Session Cookie

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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