CVE-2021-23331

Local file disclosure via world-readable temporary downloads

Published Feb 3, 2021 · Updated Sep 16, 2024

Insecure temporary files in all Square Connect Java SDK versions allow local users to read API downloads on Unix-like systems. The prepareDownloadFile method creates downloads in the shared system temporary directory with mode -rw-r--r--, exposing their contents to other accounts. Exploitation requires a multiuser host and an application call that downloads a file; exposure is limited to files produced by that path.

CVSS severity4.4
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure temporary files in all Square Connect Java SDK versions allow local users to read API downloads on Unix-like systems. The prepareDownloadFile method creates downloads in the shared system temporary directory with mode -rw-r--r--, exposing their contents to other accounts. Exploitation requires a multiuser host and an application call that downloads a file; exposure is limited to files produced by that path.

The record

CVE
CVE-2021-23331
Published
Feb 3, 2021
Updated
Sep 16, 2024
Vendor
Square
Product
Square Connect Java SDK
Classifications
CWE-377, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 3, 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=0 <unspecified

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Square · Square Connect Java SDKversion=0 <unspecified

Published CVSS scores

2.1NVDAV:L/AC:L/Au:N/C:P/I:N/A:N
4.4SnykCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
3.3NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-377Insecure Temporary File
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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