WhatsApp Cross-Site Scripting Vulnerability
Meta Platforms · WhatsApp
A cross-site scripting flaw in WhatsApp Desktop, prior to 0.3.9309 when paired with WhatsApp for iPhone prior to 2.20.10, stems from improper neutralization of input during web page generation. An attacker can use it to run script and read local files, but only by sending a specially crafted text message that the victim must interact with by clicking a link preview.
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.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 2/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 2 years after disclosure. Public exploit code (PoC-in-GitHub) appeared 39 days after disclosure.
- Disclosedday 0
- Public exploit codePoC-in-GitHub+39 days
- First seen exploitedVulnCheck KEV evidence+2 yrs
- Added to CISA KEVEU database agrees+2 yrs
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
3 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order, 3 cited passages 3ExecutionTA0002
XSS executes script in desktop client
allows cross-site scripting and local file reading
victim clicks crafted link preview
Exploiting the vulnerability requires the victim to click a link preview
CollectionTA0009
local file reading yields data
allows cross-site scripting and local file reading
Detection
0 rules for this CVE · 47 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2019-18426 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Malicious LinkT1204.0014 general rules
- Symlink Etc Passwdhightest
- Potential ClickFix Execution Pattern - Registryhighexperimental
- Suspicious ClickFix/FileFix Execution Patternhighexperimental
- Suspicious Execution via macOS Script Editormediumtest
JavaScriptT1059.00729 general rules
- Adwind RAT / JRAThightest
- Adwind RAT / JRAT File Artifacthightest
- Csc.EXE Execution Form Potentially Suspicious Parenthightest
- Cscript/Wscript Uncommon Script Extension Executionhightest
- HackTool - CACTUSTORCH Remote Thread Creationhightest
- HackTool - Koadic Executionhightest
- HTML Help HH.EXE Suspicious Child Processhightest
- JXA In-memory Execution Via OSAScripthightest
Data from Local SystemT100514 general rules
- OpenCanary - SMB File Open Requesthightest
- Potential Conti Ransomware Database Dumping Activity Via SQLCmdhightest
- SQLite Chromium Profile Data DB Accesshightest
- SQLite Firefox Profile Data DB Accesshightest
- VeeamBackup Database Credentials Dump Via Sqlcmd.EXEhightest
- Script Interpreter Spawning Credential Scanner - Linuxhighexperimental
- Script Interpreter Spawning Credential Scanner - Windowshighexperimental
- Shai-Hulud NPM Package Malicious Exfiltration via Curlhighexperimental
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- Actively_Exploited_Kev | Oct 22, 202621 Oct 2026
- 44 more on OTX