CVE-2021-31407Network attack vector

Unauthenticated bundle resource disclosure via StaticFileServer

Published Apr 23, 2021 · Updated Sep 16, 2024

Resource exposure in Vaadin Flow Server 1.2.0 through 2.4.7 and 6.0.0 through 6.0.1 allows remote attackers to read bundle contents. In OSGi deployments, StaticFileServer serves every resource exposed by ServletContext, including Java class files and static resources in the servlet's bundle, without restricting requests to intended public assets. An unauthenticated HTTP client must know an exact resource URL; the flaw discloses same-bundle classes and files but does not expose other OSGi bundles.

CVSS severity8.6
High
EPSS probability2.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exposure in Vaadin Flow Server 1.2.0 through 2.4.7 and 6.0.0 through 6.0.1 allows remote attackers to read bundle contents. In OSGi deployments, StaticFileServer serves every resource exposed by ServletContext, including Java class files and static resources in the servlet's bundle, without restricting requests to intended public assets. An unauthenticated HTTP client must know an exact resource URL; the flaw discloses same-bundle classes and files but does not expose other OSGi bundles.

The record

CVE
CVE-2021-31407
Published
Apr 23, 2021
Updated
Sep 16, 2024
Vendor
Vaadin
Product
Flow Server
Classifications
CWE-668, CWE-402, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.2.0 <* changes=[{"at":"6.0.0","status":"affected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Vaadin · Flow Serverversion=1.2.0 <* changes=[{"at":"6.0.0","status":"affected"}]
Vaadin · Vaadin Frameworkversion=12.0.0 <*; version=19.0.0

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
8.6Vaadin Ltd.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-668Exposure of Resource to Wrong Sphere
CWE-402Transmission of Private Resources into a New Sphere ('Resource Leak')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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