Vulnerability report

Exploitation attempts observed in the wild High confidence Not in CISA KEV

CVE-2021-24217

Facebook for WordPress < 3.0.0 - PHP Object Injection with POP Chain

Facebook for WordPress · affected before 3.0.0

Watch CVE-2021-24217 Browse KEV feed
Severity
CVSS 8.1 · High
Confidence
High
Exploit status
Exploitation attempts observed in the wild
EPSS
3.5%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-24217 is an unauthenticated Facebook for WordPress < 3.0.0 - PHP Object Injection with POP Chain. The run_action function of the Facebook for WordPress plugin before 3.0.0 deserializes user supplied data...

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Also reported by third-party sources. Confidence is high.

Who is affected?

Facebook for WordPress affected before 3.0.0.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Facebook for WordPress < 3.0.0 - PHP Object Injection with POP Chain

The run_action function of the Facebook for WordPress plugin before 3.0.0 deserializes user supplied data making it possible for PHP objects to be supplied creating an Object Injection vulnerability.

There was also a useable magic method in the plugin that could be used to achieve remote code execution.

Unknown Affected
Facebook for WordPress
Before 3.0.0
Published
12 Apr 2021
Exploitation Attempts Reported
25 Mar 2021
Attack vector
Remote
Complexity
High
Privileges
None
User interaction
None

Tags

wordpress php

CVE References

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation attempts observed in the wild

Wordfence

Recorded 25 Mar 2021

A trusted third party reported exploitation attempts.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
Wordfence First 2021-03-25 07:17 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

8.1 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

3.5%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Deserialization of Untrusted Data CWE-502

All CVSS Scores

CVSS v3.1 8.1 High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 6.8 Medium

AV:N/AC:M/Au:N/C:P/I:P/A:P

Timeline

From disclosure to observed exploitation attempts

  1. 14:01 UTC

    CVE published

    Vulnerability disclosed publicly

  2. 07:17 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party report of exploitation attempts

  3. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-24217

Sample API response 
{
  "cve_id": "CVE-2021-24217",
  "confidence": "High",
  "cvss_score": 8.1,
  "cvss_estimated": false,
  "epss_score": 0.0352,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}