CVE-2021-37156

Redmine 4.2.0 and 4.2.1 allow existing user sessions to continue upon enabling two-factor authentication for the user's account, but the intended behavior is for those sessions to be terminated.

Published: 2021-08-05 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-37156 is rated Moderate Risk (51.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.02%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-37156

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.25% 1.02% +0.77%
2 2025-03-30 0.39% 0.25% -0.14%
3 2025-03-29 — 0.39% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-37156

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-37156

OS Trackers for CVE-2021-37156

vendor priority summary link
debian unimportant CVE-2021-37156 unimportant priority: Debian including 1 source packages (redmine), 3 status rows across 3 suites (bookworm, sid, trixie): resolved 3. https://security-tracker.debian.org/tracker/CVE-2021-37156
ubuntu medium CVE-2021-37156 medium priority: Ubuntu including 1 source packages (redmine), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 8, needs-triage 4, ignored 3. https://ubuntu.com/security/CVE-2021-37156

Affected software / configurations for CVE-2021-37156

Vendor Product Version Raw CPE
redmine redmine 4.2.0 cpe:2.3:a:redmine:redmine:4.2.0:*:*:*:*:*:*:*
redmine redmine 4.2.1 cpe:2.3:a:redmine:redmine:4.2.1:*:*:*:*:*:*:*

References for CVE-2021-37156

cvelogic Threat Intelligence