Vulnerability report

Exploitation attempts observed in the wild Confirmed confidence In CISA KEV

CVE-2019-18426

WhatsApp Desktop Cross-Site Scripting

Facebook / WhatsApp Desktop · 0.3.9309

Watch CVE-2019-18426 Browse KEV feed
Severity
CVSS 8.2 · High
Confidence
Confirmed
Exploit status
Exploitation attempts observed in the wild
EPSS
67.9%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2019-18426 is an unauthenticated vulnerability affecting Facebook WhatsApp Desktop. A vulnerability in WhatsApp Desktop versions prior to 0.3.9309 when paired with WhatsApp for iPhone versions prior to 2.20.10...

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Listed in CISA KEV. Confidence is confirmed.

Who is affected?

Facebook / WhatsApp Desktop 0.3.9309.

What should we do?

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

Overview

WhatsApp Desktop Cross-Site Scripting

A vulnerability in WhatsApp Desktop versions prior to 0.3.9309 when paired with WhatsApp for iPhone versions prior to 2.20.10 allows cross-site scripting and local file reading.

Exploiting the vulnerability requires the victim to click a link preview from a specially crafted text message.

Facebook Affected
WhatsApp Desktop
0.3.9309 Before 0.3.9309
Published
21 Jan 2020
Exploitation Attempts Reported
23 May 2022
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
Required

Tags

cisa

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

CISA

Recorded 23 May 2022

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
CISA First 2022-05-23 00:00 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

8.2 High

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

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

EPSS

67.9%

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

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE-79

All CVSS Scores

CVSS v3.1 8.2 High

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

CVSS v2.0 5.8 Medium

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

Timeline

From disclosure to observed exploitation attempts

  1. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  2. 20:30 UTC

    CVE published

    Vulnerability disclosed publicly

  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-2019-18426

Sample API response 
{
  "cve_id": "CVE-2019-18426",
  "confidence": "Confirmed",
  "cvss_score": 8.2,
  "cvss_estimated": false,
  "epss_score": 0.67859,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}