What is the CVSS score of CVE-2021-39321?

CVE-2021-39321 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 2.0%.

Is there a public PoC exploit available for CVE-2021-39321?

Yes, a public proof-of-concept exploit is available for CVE-2021-39321. Prioritise patching immediately. EPSS: 2.0%.

Is there a patch available for CVE-2021-39321?

Yes, a patch is available for CVE-2021-39321. Update the affected software to the latest version immediately.

Sassy Social Share CVE-2021-39321

HIGH

Deserialization of Untrusted Data (CWE-502)

2021-10-21 security@wordfence.com

PHP WordPress Deserialization Sassy Social Share Wordpress Plugin Heateor

8.8

CVSS 3.1 · Vendor: wordfence

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Vulnerability Assessment

Weakness	CWE CWE-502 OWASP Top 10:2025 A08:2025 - Software or Data Integrity Failures ASVS 5.0 V1 - Encoding and Sanitization Safe deserialization, type allowlists MITRE ATT&CK 2 techniques across 2 tactics: Execution, Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 8.8 (HIGH). Attack characteristics: network attack vector, low complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	A remote attacker could execute arbitrary code through malicious serialized objects by sending crafted requests to the affected application.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 2.0% exploitation probability (EPSS)

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AnalysisAI

Version 3.3.23 of the Sassy Social Share WordPress plugin is vulnerable to PHP Object Injection via the wp_ajax_heateor_sss_import_config AJAX action due to deserialization of unvalidated user. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Avoid deserializing untrusted data. Use safe serialization formats (JSON). Implement integrity checks and type allowlists.

Affects your stack

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Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Deserialization of Untrusted Data (CWE-502), which allows attackers to execute arbitrary code through malicious serialized objects. Version 3.3.23 of the Sassy Social Share WordPress plugin is vulnerable to PHP Object Injection via the wp_ajax_heateor_sss_import_config AJAX action due to deserialization of unvalidated user supplied inputs via the import_config function found in the ~/admin/class-sassy-social-share-admin.php file. This can be exploited by underprivileged authenticated users due to a missing capability check on the import_config function. Affected products include: Heateor Sassy Social Share. Version information: Version 3.3.23.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (wordfence) PRIMARY 8.8 HIGH

AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from Vendor (wordfence) · only source for this CVE.

CVSS VectorVendor: wordfence

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

Version 3.3.23 of the Sassy Social Share WordPress plugin is vulnerable to PHP Object Injection via the wp_ajax_heateor_sss_import_config AJAX action due to deserialization of unvalidated user supplied inputs via the import_config function found in the ~/admin/class-sassy-social-share-admin.php file. This can be exploited by underprivileged authenticated users due to a missing capability check on the import_config function.

Threat Intelligence Overview

EPSS Score

2.0%

Top 22% exploitable

Exploit

POC

Public exploit code exists

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC Yes

EPSS 2.0%

Patch available Yes

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +2

CVSS: +44

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Insecure Deserialization CRITICAL

Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation.