HtmlSanitizer 8.1.870
See the version list below for details.
dotnet add package HtmlSanitizer --version 8.1.870
NuGet\Install-Package HtmlSanitizer -Version 8.1.870
<PackageReference Include="HtmlSanitizer" Version="8.1.870" />
paket add HtmlSanitizer --version 8.1.870
#r "nuget: HtmlSanitizer, 8.1.870"
// Install HtmlSanitizer as a Cake Addin #addin nuget:?package=HtmlSanitizer&version=8.1.870 // Install HtmlSanitizer as a Cake Tool #tool nuget:?package=HtmlSanitizer&version=8.1.870
HtmlSanitizer
HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. It uses AngleSharp to parse, manipulate, and render HTML and CSS.
Because HtmlSanitizer is based on a robust HTML parser it can also shield you from deliberate or accidental "tag poisoning" where invalid HTML in one fragment can corrupt the whole document leading to broken layout or style.
In order to facilitate different use cases, HtmlSanitizer can be customized at several levels:
- Configure allowed HTML tags through the property
AllowedTags
. All other tags will be stripped. - Configure allowed HTML attributes through the property
AllowedAttributes
. All other attributes will be stripped. - Configure allowed CSS property names through the property
AllowedCssProperties
. All other styles will be stripped. - Configure allowed CSS at-rules through the property
AllowedAtRules
. All other at-rules will be stripped. - Configure allowed URI schemes through the property
AllowedSchemes
. All other URIs will be stripped. - Configure HTML attributes that contain URIs (such as "src", "href" etc.) through the property
UriAttributes
. - Provide a base URI that will be used to resolve relative URIs against.
- Cancelable events are raised before a tag, attribute, or style is removed.
Usage
Install the HtmlSanitizer NuGet package. Then:
using Ganss.Xss;
var sanitizer = new HtmlSanitizer();
var html = @"<script>alert('xss')</script><div onload=""alert('xss')"""
+ @"style=""background-color: rgba(0, 0, 0, 1)"">Test<img src=""test.png"""
+ @"style=""background-image: url(javascript:alert('xss')); margin: 10px""></div>";
var sanitized = sanitizer.Sanitize(html, "https://www.example.com");
var expected = @"<div style=""background-color: rgba(0, 0, 0, 1)"">"
+ @"Test<img src=""https://www.example.com/test.png"" style=""margin: 10px""></div>";
Assert.Equal(expected, sanitized);
There's an online demo, plus there's also a .NET Fiddle you can play with.
More example code and a description of possible options can be found in the Wiki.
Tags allowed by default
a
,
abbr
,
acronym
,
address
,
area
,
article
,
aside
,
b
,
bdi
,
big
,
blockquote
,
body
,
br
,
button
,
caption
,
center
,
cite
,
code
,
col
,
colgroup
,
data
,
datalist
,
dd
,
del
,
details
,
dfn
,
dir
,
div
,
dl
,
dt
,
em
,
fieldset
,
figcaption
,
figure
,
font
,
footer
,
form
,
h1
,
h2
,
h3
,
h4
,
h5
,
h6
,
head
,
header
,
hr
,
html
,
i
,
img
,
input
,
ins
,
kbd
,
keygen
,
label
,
legend
,
li
,
main
,
map
,
mark
,
menu
,
menuitem
,
meter
,
nav
,
ol
,
optgroup
,
option
,
output
,
p
,
pre
,
progress
,
q
,
rp
,
rt
,
ruby
,
s
,
samp
,
section
,
select
,
small
,
span
,
strike
,
strong
,
sub
,
summary
,
sup
,
table
,
tbody
,
td
,
textarea
,
tfoot
,
th
,
thead
,
time
,
tr
,
tt
,
u
,
ul
,
var
,
wbr
Attributes allowed by default
abbr
,
accept-charset
,
accept
,
accesskey
,
action
,
align
,
alt
,
autocomplete
,
autosave
,
axis
,
bgcolor
,
border
,
cellpadding
,
cellspacing
,
challenge
,
char
,
charoff
,
charset
,
checked
,
cite
,
clear
,
color
,
cols
,
colspan
,
compact
,
contenteditable
,
coords
,
datetime
,
dir
,
disabled
,
draggable
,
dropzone
,
enctype
,
for
,
frame
,
headers
,
height
,
high
,
href
,
hreflang
,
hspace
,
ismap
,
keytype
,
label
,
lang
,
list
,
longdesc
,
low
,
max
,
maxlength
,
media
,
method
,
min
,
multiple
,
name
,
nohref
,
noshade
,
novalidate
,
nowrap
,
open
,
optimum
,
pattern
,
placeholder
,
prompt
,
pubdate
,
radiogroup
,
readonly
,
rel
,
required
,
rev
,
reversed
,
rows
,
rowspan
,
rules
,
scope
,
selected
,
shape
,
size
,
span
,
spellcheck
,
src
,
start
,
step
,
style
,
summary
,
tabindex
,
target
,
title
,
type
,
usemap
,
valign
,
value
,
vspace
,
width
,
wrap
Note: to prevent classjacking and interference with classes where the sanitized fragment is to be integrated, the class
attribute is disallowed by default.
It can be added as follows:
var sanitizer = new HtmlSanitizer();
sanitizer.AllowedAttributes.Add("class");
var sanitized = sanitizer.Sanitize(html);
CSS properties allowed by default
align-content
,
align-items
,
align-self
,
all
,
animation
,
animation-delay
,
animation-direction
,
animation-duration
,
animation-fill-mode
,
animation-iteration-count
,
animation-name
,
animation-play-state
,
animation-timing-function
,
backface-visibility
,
background
,
background-attachment
,
background-blend-mode
,
background-clip
,
background-color
,
background-image
,
background-origin
,
background-position
,
background-position-x
,
background-position-y
,
background-repeat
,
background-repeat-x
,
background-repeat-y
,
background-size
,
border
,
border-bottom
,
border-bottom-color
,
border-bottom-left-radius
,
border-bottom-right-radius
,
border-bottom-style
,
border-bottom-width
,
border-collapse
,
border-color
,
border-image
,
border-image-outset
,
border-image-repeat
,
border-image-slice
,
border-image-source
,
border-image-width
,
border-left
,
border-left-color
,
border-left-style
,
border-left-width
,
border-radius
,
border-right
,
border-right-color
,
border-right-style
,
border-right-width
,
border-spacing
,
border-style
,
border-top
,
border-top-color
,
border-top-left-radius
,
border-top-right-radius
,
border-top-style
,
border-top-width
,
border-width
,
bottom
,
box-decoration-break
,
box-shadow
,
box-sizing
,
break-after
,
break-before
,
break-inside
,
caption-side
,
caret-color
,
clear
,
clip
,
color
,
column-count
,
column-fill
,
column-gap
,
column-rule
,
column-rule-color
,
column-rule-style
,
column-rule-width
,
column-span
,
column-width
,
columns
,
content
,
counter-increment
,
counter-reset
,
cursor
,
direction
,
display
,
empty-cells
,
filter
,
flex
,
flex-basis
,
flex-direction
,
flex-flow
,
flex-grow
,
flex-shrink
,
flex-wrap
,
float
,
font
,
font-family
,
font-feature-settings
,
font-kerning
,
font-language-override
,
font-size
,
font-size-adjust
,
font-stretch
,
font-style
,
font-synthesis
,
font-variant
,
font-variant-alternates
,
font-variant-caps
,
font-variant-east-asian
,
font-variant-ligatures
,
font-variant-numeric
,
font-variant-position
,
font-weight
,
gap
,
grid
,
grid-area
,
grid-auto-columns
,
grid-auto-flow
,
grid-auto-rows
,
grid-column
,
grid-column-end
,
grid-column-gap
,
grid-column-start
,
grid-gap
,
grid-row
,
grid-row-end
,
grid-row-gap
,
grid-row-start
,
grid-template
,
grid-template-areas
,
grid-template-columns
,
grid-template-rows
,
hanging-punctuation
,
height
,
hyphens
,
image-rendering
,
isolation
,
justify-content
,
left
,
letter-spacing
,
line-break
,
line-height
,
list-style
,
list-style-image
,
list-style-position
,
list-style-type
,
margin
,
margin-bottom
,
margin-left
,
margin-right
,
margin-top
,
mask
,
mask-clip
,
mask-composite
,
mask-image
,
mask-mode
,
mask-origin
,
mask-position
,
mask-repeat
,
mask-size
,
mask-type
,
max-height
,
max-width
,
min-height
,
min-width
,
mix-blend-mode
,
object-fit
,
object-position
,
opacity
,
order
,
orphans
,
outline
,
outline-color
,
outline-offset
,
outline-style
,
outline-width
,
overflow
,
overflow-wrap
,
overflow-x
,
overflow-y
,
padding
,
padding-bottom
,
padding-left
,
padding-right
,
padding-top
,
page-break-after
,
page-break-before
,
page-break-inside
,
perspective
,
perspective-origin
,
pointer-events
,
position
,
quotes
,
resize
,
right
,
row-gap
,
scroll-behavior
,
tab-size
,
table-layout
,
text-align
,
text-align-last
,
text-combine-upright
,
text-decoration
,
text-decoration-color
,
text-decoration-line
,
text-decoration-skip
,
text-decoration-style
,
text-indent
,
text-justify
,
text-orientation
,
text-overflow
,
text-shadow
,
text-transform
,
text-underline-position
,
top
,
transform
,
transform-origin
,
transform-style
,
transition
,
transition-delay
,
transition-duration
,
transition-property
,
transition-timing-function
,
unicode-bidi
,
user-select
,
vertical-align
,
visibility
,
white-space
,
widows
,
width
,
word-break
,
word-spacing
,
word-wrap
,
writing-mode
,
z-index
CSS at-rules allowed by default
namespace
, style
style
refers to style declarations within other at-rules such as @media
. Disallowing @namespace
while allowing other types of at-rules can lead to errors.
Property declarations in @font-face
and @viewport
are not sanitized.
Note: the style
tag is disallowed by default.
URI schemes allowed by default
http
, https
Note: Protocol-relative URLs (e.g. <a href="//github.com">//github.com</a>) are allowed by default (as are other relative URLs).
to allow mailto:
links:
sanitizer.AllowedSchemes.Add("mailto");
Default attributes that contain URIs
action
, background
, dynsrc
, href
, lowsrc
, src
Thread safety
The Sanitize()
and SanitizeDocument()
methods are thread-safe, i.e. you can use these methods on a single shared instance from different threads provided you do not simultaneously set instance or static properties. A typical use case is that you prepare an HtmlSanitizer
instance once (i.e. set desired properties such as AllowedTags
etc.) from a single thread, then call Sanitize()
/SanitizeDocument()
from multiple threads.
Text content not necessarily preserved as-is
Please note that as the input is parsed by AngleSharp's HTML parser and then rendered back out, you cannot expect the text content to be preserved exactly as it was input, even if no elements or attributes were removed. Examples:
4 < 5
becomes4 < 5
<SPAN>test</p>
becomes<span>test<p></p></span>
<span title='test'>test</span>
becomes<span title="test">test</span>
On the other hand, although some broken HTML is fixed by the parser, the output might still contain invalid HTML. Examples:
<div><li>test</li></div>
<ul><br><li>test</li></ul>
<h3><p>test</p></h3>
License
Product | Versions Compatible and additional computed target framework versions. |
---|---|
.NET | net5.0 was computed. net5.0-windows was computed. net6.0 was computed. net6.0-android was computed. net6.0-ios was computed. net6.0-maccatalyst was computed. net6.0-macos was computed. net6.0-tvos was computed. net6.0-windows was computed. net7.0 was computed. net7.0-android was computed. net7.0-ios was computed. net7.0-maccatalyst was computed. net7.0-macos was computed. net7.0-tvos was computed. net7.0-windows was computed. net8.0 was computed. net8.0-android was computed. net8.0-browser was computed. net8.0-ios was computed. net8.0-maccatalyst was computed. net8.0-macos was computed. net8.0-tvos was computed. net8.0-windows was computed. |
.NET Core | netcoreapp2.0 was computed. netcoreapp2.1 was computed. netcoreapp2.2 was computed. netcoreapp3.0 was computed. netcoreapp3.1 was computed. |
.NET Standard | netstandard2.0 is compatible. netstandard2.1 was computed. |
.NET Framework | net461 is compatible. net462 was computed. net463 was computed. net47 was computed. net471 was computed. net472 was computed. net48 was computed. net481 was computed. |
MonoAndroid | monoandroid was computed. |
MonoMac | monomac was computed. |
MonoTouch | monotouch was computed. |
Tizen | tizen40 was computed. tizen60 was computed. |
Xamarin.iOS | xamarinios was computed. |
Xamarin.Mac | xamarinmac was computed. |
Xamarin.TVOS | xamarintvos was computed. |
Xamarin.WatchOS | xamarinwatchos was computed. |
-
.NETFramework 4.6.1
- AngleSharp (= 0.17.1)
- AngleSharp.Css (= 0.17.0)
- System.Collections.Immutable (>= 8.0.0)
-
.NETStandard 2.0
- AngleSharp (= 0.17.1)
- AngleSharp.Css (= 0.17.0)
- System.Collections.Immutable (>= 8.0.0)
NuGet packages (132)
Showing the top 5 NuGet packages that depend on HtmlSanitizer:
Package | Downloads |
---|---|
FenixAlliance.ACL.Dependencies
Application Component for the Alliance Business Suite. |
|
OrchardCore.Infrastructure
Orchard Core CMS is a Web Content Management System (CMS) built on top of the Orchard Core Framework. Implementation for OrchardCoreCMS Infrastructure |
|
Kentico.Xperience.AspNetCore.WebApp
Contains assemblies and content items required to integrate Kentico Xperience into ASP.NET Core applications. |
|
OrchardCore.Application.Cms.Core.Targets
Orchard Core CMS is a Web Content Management System (CMS) built on top of the Orchard Core Framework. Converts the application into a modular OrchardCore CMS application with TheAdmin theme but without any front-end Themes. |
|
TheTheme
Orchard Core CMS is a Web Content Management System (CMS) built on top of the Orchard Core Framework. The default Theme - Can be used as base theme for new themes. |
GitHub repositories (27)
Showing the top 5 popular GitHub repositories that depend on HtmlSanitizer:
Repository | Stars |
---|---|
abpframework/abp
Open-source web application framework for ASP.NET Core! Offers an opinionated architecture to build enterprise software solutions with best practices on top of the .NET. Provides the fundamental infrastructure, cross-cutting-concern implementations, startup templates, application modules, UI themes, tooling and documentation.
|
|
aspnetboilerplate/aspnetboilerplate
ASP.NET Boilerplate - Web Application Framework
|
|
dodyg/practical-aspnetcore
Practical samples of ASP.NET Core 9 RC1, 8.0, 7.0, 6.0, 5.0, 3.1, 2.2, and 2.1,projects you can use. Readme contains explanations on all projects.
|
|
OrchardCMS/OrchardCore
Orchard Core is an open-source modular and multi-tenant application framework built with ASP.NET Core, and a content management system (CMS) built on top of that framework.
|
|
btcpayserver/btcpayserver
Accept Bitcoin payments. Free, open-source & self-hosted, Bitcoin payment processor.
|
Version | Downloads | Last updated | |
---|---|---|---|
8.2.871-beta | 17,871 | 7/26/2024 | |
8.1.870 | 557,919 | 7/26/2024 | |
8.1.866-beta | 41,595 | 4/16/2024 | |
8.1.860-beta | 23,730 | 3/18/2024 | |
8.1.844-beta | 77,755 | 2/12/2024 | |
8.1.839-beta | 4,144 | 2/1/2024 | |
8.1.812-beta | 98,396 | 12/20/2023 | |
8.1.796-beta | 92,744 | 11/24/2023 | |
8.1.748-beta | 37,199 | 10/27/2023 | |
8.1.747-beta | 2,936 | 10/24/2023 | |
8.1.745-beta | 468 | 10/23/2023 | |
8.1.722-beta | 8,496 | 10/4/2023 | |
8.1.719-beta | 789 | 9/25/2023 | |
8.1.717-beta | 843 | 9/25/2023 | |
8.0.865 | 1,708,205 | 4/16/2024 | |
8.0.843 | 1,359,683 | 2/12/2024 | |
8.0.838 | 310,496 | 2/1/2024 | |
8.0.811 | 952,014 | 12/20/2023 | |
8.0.795 | 1,037,128 | 11/24/2023 | |
8.0.746 | 2,685,973 | 10/24/2023 | |
8.0.744 | 82,629 | 10/23/2023 | |
8.0.723 | 1,733,434 | 10/4/2023 | |
8.0.718 | 84,172 | 9/25/2023 | |
8.0.692 | 720,454 | 8/3/2023 | |
8.0.691-beta | 1,777 | 8/3/2023 | |
8.0.690-beta | 600 | 8/3/2023 | |
8.0.645 | 3,696,040 | 1/17/2023 | |
8.0.601 | 1,976,096 | 10/12/2022 | |
7.1.542 | 2,334,402 | 7/12/2022 | |
7.1.512 | 1,173,316 | 6/3/2022 | |
7.1.509 | 53,147 | 6/1/2022 | |
7.1.488 | 2,337,647 | 2/24/2022 | |
7.1.475 | 618,502 | 1/25/2022 | |
7.0.473 | 507,935 | 1/6/2022 | |
7.0.470-beta | 65,277 | 12/1/2021 | |
6.0.453 | 1,993,671 | 11/3/2021 | |
6.0.441 | 2,384,730 | 8/11/2021 | |
6.0.437 | 310,785 | 8/6/2021 | |
6.0.430-beta | 73,559 | 6/14/2021 | |
6.0.423-beta | 872 | 6/12/2021 | |
6.0.409-beta | 3,628 | 4/23/2021 | |
5.0.404 | 2,213,605 | 4/23/2021 | |
5.0.376 | 3,059,761 | 1/15/2021 | |
5.0.372 | 1,429,654 | 12/23/2020 |