No exploitation reportedFix available

CVE-2021-31864

Q: Is CVE-2021-31864 actively exploited?

Active exploitation of CVE-2021-31864 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-31864?

CVE-2021-31864 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

No exploitation reported by the sources we read.

Published2021-04-28
Fixed in4.2.1 · 4.1.3 · 4.0.9

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Redmine before 4.0.9, 4.1.x before 4.1.3, and 4.2.x before 4.2.1 allows attackers to bypass the add_issue_notes permission requirement by leveraging the incoming mail handler.

Timeline

dates in UTC

2021-04-2807:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-31864?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-31864?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Redmine

Branch	Affected	Fixed in	Source
4.2	≥ 4.2.0, < 4.2.1	4.2.1	NVD · OSV
4.1	≥ 4.1.0, < 4.1.3	4.1.3	NVD · OSV
4.0	< 4.0.9	4.0.9	NVD · OSV

Debian debian linux

Branch	Affected	Fixed in	Source
9.0	= 9.0	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Redmine to 4.2.1 · 4.1.3 · 4.0.9

Advisories and patches

www.redmine.orgVendor Advisory
www.redmine.orgVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.15.3read 2026-10-23
NVDCVSS 2.05read 2026-10-23
FIRST EPSSEPSS score1.2 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Published: 2021-04-28
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-31864?

Redmine before 4.0.9, 4.1.x before 4.1.3, and 4.2.x before 4.2.1 allows attackers to bypass the add_issue_notes permission requirement by leveraging the incoming mail handler.

Is CVE-2021-31864 actively exploited?

Active exploitation of CVE-2021-31864 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-31864?

CVE-2021-31864 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

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