MEDIUM
CVE-2021-31866
CWE-203Published: April 28, 2021· Updated: Jun 17, 2026
5.3
CVSS v3.1
Official Description
Redmine before 4.0.9 and 4.1.x before 4.1.3 allows an attacker to learn the values of internal authentication keys by observing timing differences in string comparison operations within SysController and MailHandlerController.
Technical Analysis
CVE-2021-31866 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Affected Vendors & Products
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
ADVISORYhttps://www.redmine.org/news/131
ADVISORYhttps://www.redmine.org/news/131
All References (6)
→
https://lists.debian.org/debian-lts-announce/2021/05/msg00013.htmlMailing List · Third Party Advisory
→
https://www.redmine.org/news/131Vendor Advisory
→
https://lists.debian.org/debian-lts-announce/2021/05/msg00013.htmlMailing List · Third Party Advisory
→
https://www.redmine.org/news/131Vendor Advisory
Quick Facts
CVE IDCVE-2021-31866
CVSS Score5.3 / 10
SeverityMEDIUM
WeaknessCWE-203
CISA KEVNo
Affected2 vendor(s)
PublishedApr 28, 2021
Related CVEs (CWE-203)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-31866 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.