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Fencer Intel
high 8.8

CVE-2020-16873 json

Xamarin.Forms Spoofing Vulnerability

published 6y ago modified 4mo ago also EUVD-2020-8831

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
4.0%
EPSS 4.0% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

<p>A spoofing vulnerability manifests in Microsoft Xamarin.Forms due to the default settings on Android WebView version prior to 83.0.4103.106. This vulnerability could allow an attacker to execute arbitrary Javascript code on a target system.</p> <p>For the attack to be successful, the targeted user would need to browse to a malicious website or a website serving the malicious code through Xamarin.Forms.</p> <p>The security update addresses this vulnerability by preventing the malicious Javascript from running in the WebView.</p>

Patch / fix

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Exploit prediction

3.97% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.7 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N/E:F/RL:O/RC:C/CR:M/MAV:N/MAC:L/MPR:N/MUI:R/MS:C
CNA 3.1 4.7 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • Microsoft xamarin.forms

Classification

Weakness
  • CWE-1188 Initialization of a Resource with an Insecure Default

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.