What is CVE-2019-18426?

CVE-2019-18426 is a high-severity vulnerability in Facebook Whatsapp Desktop, classified under Cross-site Scripting. CVSS score: 8.2/10. Published 2020-01-21.

How severe is CVE-2019-18426?

High severity. CVSS v3 base score is 8.2 out of 10.

Is CVE-2019-18426 known to be exploited?

Yes. CVE-2019-18426 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-05-23), indicating it is being actively exploited. 12 public proof-of-concept repositories are indexed.

XSS in Facebook Whatsapp Desktop

CVE-2019-18426

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-01-21 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N.

EPSS exploit prediction

EPSS: 0.679 (99.3th percentile), scored 2026-10-18.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.679 · newest: 0.679 · change: 0.000

Affected products

Facebook Whatsapp Desktop — versions 0.3.9309, unspecified
Whatsapp

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2022-05-23. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-06-13.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

www.facebook.com/security/advisories/cve-2019-18426 (Vendor Advisory)
packetstormsecurity.com/files/157097/WhatsApp-Desktop-0.3.9308-Cross-Site-Scrip… (Exploit, VDB Entry, Third Party Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2019-18426?: CVE-2019-18426 is a high-severity vulnerability in Facebook Whatsapp Desktop, classified under Cross-site Scripting. CVSS score: 8.2/10. Published 2020-01-21.
How severe is CVE-2019-18426?: High severity. CVSS v3 base score is 8.2 out of 10.
Is CVE-2019-18426 known to be exploited?: Yes. CVE-2019-18426 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-05-23), indicating it is being actively exploited. 12 public proof-of-concept repositories are indexed.