LOW
CVE-2021-31406
CWE-208Published: April 23, 2021· Updated: Jun 17, 2026
2.5
CVSS v3.1
Official Description
Non-constant-time comparison of CSRF tokens in endpoint request handler in com.vaadin:flow-server versions 3.0.0 through 5.0.3 (Vaadin 15.0.0 through 18.0.6), and com.vaadin:fusion-endpoint version 6.0.0 (Vaadin 19.0.0) allows attacker to guess a security token for Fusion endpoints via timing attack.
Technical Analysis
CVE-2021-31406 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorLocal
Attack ComplexityHigh
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
Affected Vendors & Products
vaadin2 product(s)
flowvaadin
Source: NVD CPE · 4 total CPE entries
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
All References (4)
→
https://github.com/vaadin/flow/pull/10157Patch · Third Party Advisory
→
https://vaadin.com/security/cve-2021-31406Vendor Advisory
→
https://github.com/vaadin/flow/pull/10157Patch · Third Party Advisory
→
https://vaadin.com/security/cve-2021-31406Vendor Advisory
Quick Facts
CVE IDCVE-2021-31406
CVSS Score2.5 / 10
SeverityLOW
WeaknessCWE-208
CISA KEVNo
Affected1 vendor(s)
PublishedApr 23, 2021
Related CVEs (CWE-208)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-31406 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.COM. CVE data is provided under the NVD usage policy.