How severe is CVE-2021-23331?

CVE-2021-23331 has a CVSS score of 3.3/10, rated LOW. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-23331?

CVE-2021-23331 affects the following packages: com.squareup:connect (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-23331?

No patched version of com.squareup:connect has shipped for CVE-2021-23331 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2021-23331 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.squareup:connect, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-23331 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2021-23331 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-23331 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-23331?

CVE-2021-23331 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 26th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2021-23331 published, and has it been updated?

CVE-2021-23331 was published on June 16, 2021 and was last updated on March 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

LOW severity

CVE-2021-23331 — connect

LOW

CVE-2021-23331 is a low-severity (CVSS 3.3) vulnerability in com.squareup:connect. No vendor fix is recorded yet; mitigation options are listed below.

Insecure temporary file used in com.squareup:connect

Published

Jun 16, 2021

Updated

Mar 13, 2026

Affected

1 pkg

Patched

See advisory

Exploits

None indexed

Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs26th percentile — riskier than 26% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-23331 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

☕com.squareup:connect

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

This affects all versions of package com.squareup:connect. The method prepareDownloadFilecreates creates a temporary file with the permissions bits of -rw-r--r-- on unix-like systems. On unix-like systems, the system temporary directory is shared between users. As such, the contents of the file downloaded by downloadFileFromResponse will be visible to all other users on the local system. A workaround fix for this issue is to set the system property java.io.tmpdir to a safe directory as remediation. Note: This version of the SDK is end of life and no longer maintained, please upgrade to the latest version.

Affected Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`com.squareup:connect`	all versions	No fix

Affected Products

1 product · 1 configurations

Application

connect java software development kitsquareup

all

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.squareup:connect, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of com.squareup:connect has shipped for CVE-2021-23331 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-23331 in your dependencies?

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