CVE-2021-31411 | Insecure temporary directory usage in frontend build functionality of Vaadin 14 and 15-19

Insecure temporary directory usage in frontend build functionality of com.vaadin:flow-server versions 2.0.9 through 2.5.2 (Vaadin 14.0.3 through Vaadin 14.5.2), 3.0 prior to 6.0 (Vaadin 15 prior to 19), and 6.0.0 through 6.0.5 (Vaadin 19.0.0 through 19.0.4) allows local users to inject malicious code into frontend resources during application rebuilds.

Published: 2021-05-05 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-31411 is rated Low Risk (29.4/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.05%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2021-31411

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 2025-03-30 0.10% 0.05% -0.05%
2 2025-03-29 0.04% 0.10% +0.05%
3 2023-03-07 — 0.04% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-31411

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.3 3.1 MEDIUM
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
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:H)
Serious risk that confidential data gets exposed in a big 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.
 1.0 5.2 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:L)
A normal user session is enough; they don’t have to be admin.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
4.6 2.0 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.9 6.4 [email protected]

Weakness enumeration for CVE-2021-31411

GitHub Security Advisory for CVE-2021-31411

GHSA-p826-8vhq-h439 · Severity: high · Ecosystem: maven — Insecure temporary directory usage in frontend build functionality of Vaadin 14 and 15-19

Affected software / configurations for CVE-2021-31411

Vendor Product Version Raw CPE
vaadin flow >= 2.0.9, < 2.5.3 cpe:2.3:a:vaadin:flow:*:*:*:*:*:*:*:*
vaadin flow >= 3.0.0, <= 5.0.0 cpe:2.3:a:vaadin:flow:*:*:*:*:*:*:*:*
vaadin flow >= 6.0.0, <= 6.0.6 cpe:2.3:a:vaadin:flow:*:*:*:*:*:*:*:*
vaadin vaadin >= 14.0.3, < 14.5.3 cpe:2.3:a:vaadin:vaadin:*:*:*:*:*:*:*:*
vaadin vaadin >= 15.0.0, < 19.0.5 cpe:2.3:a:vaadin:vaadin:*:*:*:*:*:*:*:*

References for CVE-2021-31411

cvelogic Threat Intelligence