diff --git a/package.json b/package.json
index 68a1b13a1..7dc7fa66a 100644
--- a/package.json
+++ b/package.json
@@ -95,7 +95,7 @@
     "react-dom": "^15.6.0",
     "react-gemini-scrollbar": "github:matrix-org/react-gemini-scrollbar#5e97aef",
     "resize-observer-polyfill": "^1.5.0",
-    "sanitize-html": "^1.18.4",
+    "sanitize-html": "^2.3.2",
     "slate": "^0.41.2",
     "slate-html-serializer": "^0.6.1",
     "slate-md-serializer": "github:matrix-org/slate-md-serializer#f7c4ad3",
diff --git a/yarn.lock b/yarn.lock
index 09d3ae60d..1370d5e98 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -605,7 +605,7 @@ array-union@^1.0.2:
   dependencies:
     array-uniq "^1.0.1"
 
-array-uniq@^1.0.1, array-uniq@^1.0.2:
+array-uniq@^1.0.1:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/array-uniq/-/array-uniq-1.0.3.tgz#af6ac877a25cc7f74e058894753858dfdb24fdb6"
   integrity sha1-r2rId6Jcx/dOBYiUdThY39sk/bY=
@@ -1997,6 +1997,11 @@ color-name@1.1.3:
   resolved "https://registry.yarnpkg.com/color-name/-/color-name-1.1.3.tgz#a7d0558bd89c42f795dd42328f740831ca53bc25"
   integrity sha1-p9BVi9icQveV3UIyj3QIMcpTvCU=
 
+colorette@^1.2.2:
+  version "1.2.2"
+  resolved "https://registry.yarnpkg.com/colorette/-/colorette-1.2.2.tgz#cbcc79d5e99caea2dbf10eb3a26fd8b3e6acfa94"
+  integrity sha512-MKGMzyfeuutC/ZJ1cba9NqcNpfeqMUcYmyF1ZFY6/Cn7CNSAKx6a+s48sqLqyAiZuaP2TcqMhoo+dlwFnVxT9w==
+
 colors@^1.1.0, colors@^1.1.2:
   version "1.3.3"
   resolved "https://registry.yarnpkg.com/colors/-/colors-1.3.3.tgz#39e005d546afe01e01f9c4ca8fa50f686a01205d"
@@ -2354,6 +2359,11 @@ deep-is@~0.1.3:
   resolved "https://registry.yarnpkg.com/deep-is/-/deep-is-0.1.3.tgz#b369d6fb5dbc13eecf524f91b070feedc357cf34"
   integrity sha1-s2nW+128E+7PUk+RsHD+7cNXzzQ=
 
+deepmerge@^4.2.2:
+  version "4.2.2"
+  resolved "https://registry.yarnpkg.com/deepmerge/-/deepmerge-4.2.2.tgz#44d2ea3679b8f4d4ffba33f03d865fc1e7bf4955"
+  integrity sha512-FJ3UgI4gIl+PHZm53knsuSFpE+nESMr7M4v9QcgB7S63Kj/6WqMiFQJpBBYz1Pt+66bZpP3Q7Lye0Oo9MPKEdg==
+
 define-properties@^1.1.2, define-properties@^1.1.3, define-properties@~1.1.2:
   version "1.1.3"
   resolved "https://registry.yarnpkg.com/define-properties/-/define-properties-1.1.3.tgz#cf88da6cbee26fe6db7094f61d870cbd84cee9f1"
@@ -2491,6 +2501,15 @@ dom-serializer@0:
     domelementtype "^1.3.0"
     entities "^1.1.1"
 
+dom-serializer@^1.0.1:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/dom-serializer/-/dom-serializer-1.3.1.tgz#d845a1565d7c041a95e5dab62184ab41e3a519be"
+  integrity sha512-Pv2ZluG5ife96udGgEDovOOOA5UELkltfJpnIExPrAk1LTvecolUGn6lIaoLh86d83GiB86CjzciMd9BuRB71Q==
+  dependencies:
+    domelementtype "^2.0.1"
+    domhandler "^4.0.0"
+    entities "^2.0.0"
+
 domain-browser@^1.1.1:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/domain-browser/-/domain-browser-1.2.0.tgz#3d31f50191a6749dd1375a7f522e823d42e54eda"
@@ -2501,6 +2520,11 @@ domelementtype@1, domelementtype@^1.3.0, domelementtype@^1.3.1:
   resolved "https://registry.yarnpkg.com/domelementtype/-/domelementtype-1.3.1.tgz#d048c44b37b0d10a7f2a3d5fee3f4333d790481f"
   integrity sha512-BSKB+TSpMpFI/HOxCNr1O8aMOTZ8hT3pM3GQ0w/mWRmkhEDSFJkkyzz4XQsBV44BChwGkrDfMyjVD0eA2aFV3w==
 
+domelementtype@^2.0.1, domelementtype@^2.2.0:
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/domelementtype/-/domelementtype-2.2.0.tgz#9a0b6c2782ed6a1c7323d42267183df9bd8b1d57"
+  integrity sha512-DtBMo82pv1dFtUmHyr48beiuq792Sxohr+8Hm9zoxklYPfa6n0Z3Byjj2IV7bmr2IyqClnqEQhfgHJJ5QF0R5A==
+
 domhandler@^2.3.0:
   version "2.4.2"
   resolved "https://registry.yarnpkg.com/domhandler/-/domhandler-2.4.2.tgz#8805097e933d65e85546f726d60f5eb88b44f803"
@@ -2508,6 +2532,13 @@ domhandler@^2.3.0:
   dependencies:
     domelementtype "1"
 
+domhandler@^4.0.0, domhandler@^4.2.0:
+  version "4.2.0"
+  resolved "https://registry.yarnpkg.com/domhandler/-/domhandler-4.2.0.tgz#f9768a5f034be60a89a27c2e4d0f74eba0d8b059"
+  integrity sha512-zk7sgt970kzPks2Bf+dwT/PLzghLnsivb9CcxkvR8Mzr66Olr0Ofd8neSbglHJHaHa2MadfoSdNlKYAaafmWfA==
+  dependencies:
+    domelementtype "^2.2.0"
+
 domutils@^1.5.1:
   version "1.7.0"
   resolved "https://registry.yarnpkg.com/domutils/-/domutils-1.7.0.tgz#56ea341e834e06e6748af7a1cb25da67ea9f8c2a"
@@ -2516,6 +2547,15 @@ domutils@^1.5.1:
     dom-serializer "0"
     domelementtype "1"
 
+domutils@^2.5.2:
+  version "2.6.0"
+  resolved "https://registry.yarnpkg.com/domutils/-/domutils-2.6.0.tgz#2e15c04185d43fb16ae7057cb76433c6edb938b7"
+  integrity sha512-y0BezHuy4MDYxh6OvolXYsH+1EMGmFbwv5FKW7ovwMG6zTPWqNPq3WF9ayZssFq+UlKdffGLbOEaghNdaOm1WA==
+  dependencies:
+    dom-serializer "^1.0.1"
+    domelementtype "^2.2.0"
+    domhandler "^4.2.0"
+
 dot-prop@^4.1.1:
   version "4.2.0"
   resolved "https://registry.yarnpkg.com/dot-prop/-/dot-prop-4.2.0.tgz#1f19e0c2e1aa0e32797c49799f2837ac6af69c57"
@@ -2662,6 +2702,11 @@ entities@^1.1.1, "entities@~ 1.1.1":
   resolved "https://registry.yarnpkg.com/entities/-/entities-1.1.2.tgz#bdfa735299664dfafd34529ed4f8522a275fea56"
   integrity sha512-f2LZMYl1Fzu7YSBKg+RoROelpOaNrcGmE9AZubeDfrCEia483oW4MI4VyFd5VNHIgQ/7qm1I0wUHK1eJnn2y2w==
 
+entities@^2.0.0:
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/entities/-/entities-2.2.0.tgz#098dc90ebb83d8dffa089d55256b351d34c4da55"
+  integrity sha512-p92if5Nz619I0w+akJrLZH0MX0Pb5DX39XOwQTtXSdQQOaYH03S1uIQp4mhOZtAXrxq4ViO67YTiLBo2638o9A==
+
 errno@^0.1.3, errno@~0.1.7:
   version "0.1.7"
   resolved "https://registry.yarnpkg.com/errno/-/errno-0.1.7.tgz#4684d71779ad39af177e3f007996f7c67c852618"
@@ -2707,6 +2752,11 @@ escape-string-regexp@1.0.5, escape-string-regexp@^1.0.2, escape-string-regexp@^1
   resolved "https://registry.yarnpkg.com/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz#1b61c0562190a8dff6ae3bb2cf0200ca130b86d4"
   integrity sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=
 
+escape-string-regexp@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/escape-string-regexp/-/escape-string-regexp-4.0.0.tgz#14ba83a5d373e3d311e5afca29cf5bfad965bf34"
+  integrity sha512-TtpcNJ3XAzx3Gq8sWRzJaVajRs0uVxA2YAkdb1jm2YkPz4G6egUFAyA3n5vtEIZefPk5Wa4UXbKuS5fKkJWdgA==
+
 eslint-config-google@^0.7.1:
   version "0.7.1"
   resolved "https://registry.yarnpkg.com/eslint-config-google/-/eslint-config-google-0.7.1.tgz#5598f8498e9e078420f34b80495b8d959f651fb2"
@@ -3752,6 +3802,16 @@ htmlparser2@^3.10.0:
     inherits "^2.0.1"
     readable-stream "^3.1.1"
 
+htmlparser2@^6.0.0:
+  version "6.1.0"
+  resolved "https://registry.yarnpkg.com/htmlparser2/-/htmlparser2-6.1.0.tgz#c4d762b6c3371a05dbe65e94ae43a9f845fb8fb7"
+  integrity sha512-gyyPk6rgonLFEDGoeRgQNaEUvdJ4ktTmmUh/h2t7s+M8oPpIPxgNACWa+6ESR57kXstwqPiCut0V8NRpcwgU7A==
+  dependencies:
+    domelementtype "^2.0.1"
+    domhandler "^4.0.0"
+    domutils "^2.5.2"
+    entities "^2.0.0"
+
 http-errors@1.7.2:
   version "1.7.2"
   resolved "https://registry.yarnpkg.com/http-errors/-/http-errors-1.7.2.tgz#4f5029cf13239f31036e5b2e55292bcfbcc85c8f"
@@ -4215,6 +4275,11 @@ is-plain-object@^2.0.1, is-plain-object@^2.0.3, is-plain-object@^2.0.4:
   dependencies:
     isobject "^3.0.1"
 
+is-plain-object@^5.0.0:
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/is-plain-object/-/is-plain-object-5.0.0.tgz#4427f50ab3429e9025ea7d52e9043a9ef4159344"
+  integrity sha512-VRSzKkbMm5jMDoKLbltAkFQ5Qr7VDiTFGXxYFXXowVj387GeGNOCsOH6Msy00SGZ3Fp84b1Naa1psqgcCIEP5Q==
+
 is-posix-bracket@^0.1.0:
   version "0.1.1"
   resolved "https://registry.yarnpkg.com/is-posix-bracket/-/is-posix-bracket-0.1.1.tgz#3334dc79774368e92f016e6fbc0a88f5cd6e6bc4"
@@ -4626,6 +4691,11 @@ kind-of@^6.0.0, kind-of@^6.0.2:
   resolved "https://registry.yarnpkg.com/kind-of/-/kind-of-6.0.2.tgz#01146b36a6218e64e58f3a8d66de5d7fc6f6d051"
   integrity sha512-s5kLOcnH0XqDO+FvuaLX8DDjZ18CGFk7VygH40QoKPUQhW4e2rvM0rwUq0t8IQDOwYSeLK01U90OjzBTme2QqA==
 
+klona@^2.0.3:
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/klona/-/klona-2.0.4.tgz#7bb1e3affb0cb8624547ef7e8f6708ea2e39dfc0"
+  integrity sha512-ZRbnvdg/NxqzC7L9Uyqzf4psi1OM4Cuc+sJAkQPjO6XkQIJTNbfK2Rsmbw8fx1p2mkZdp2FZYo2+LwXYY/uwIA==
+
 known-css-properties@^0.11.0:
   version "0.11.0"
   resolved "https://registry.yarnpkg.com/known-css-properties/-/known-css-properties-0.11.0.tgz#0da784f115ea77c76b81536d7052e90ee6c86a8a"
@@ -4705,36 +4775,11 @@ lodash-es@^4.2.1:
   resolved "https://registry.yarnpkg.com/lodash-es/-/lodash-es-4.17.11.tgz#145ab4a7ac5c5e52a3531fb4f310255a152b4be0"
   integrity sha512-DHb1ub+rMjjrxqlB3H56/6MXtm1lSksDp2rA2cNWjG8mlDUYFhUj3Di2Zn5IwSU87xLv8tNIQ7sSwE/YOX/D/Q==
 
-lodash.clonedeep@^4.5.0:
-  version "4.5.0"
-  resolved "https://registry.yarnpkg.com/lodash.clonedeep/-/lodash.clonedeep-4.5.0.tgz#e23f3f9c4f8fbdde872529c1071857a086e5ccef"
-  integrity sha1-4j8/nE+Pvd6HJSnBBxhXoIblzO8=
-
-lodash.escaperegexp@^4.1.2:
-  version "4.1.2"
-  resolved "https://registry.yarnpkg.com/lodash.escaperegexp/-/lodash.escaperegexp-4.1.2.tgz#64762c48618082518ac3df4ccf5d5886dae20347"
-  integrity sha1-ZHYsSGGAglGKw99Mz11YhtriA0c=
-
 lodash.get@^4.4.2:
   version "4.4.2"
   resolved "https://registry.yarnpkg.com/lodash.get/-/lodash.get-4.4.2.tgz#2d177f652fa31e939b4438d5341499dfa3825e99"
   integrity sha1-LRd/ZS+jHpObRDjVNBSZ36OCXpk=
 
-lodash.isplainobject@^4.0.6:
-  version "4.0.6"
-  resolved "https://registry.yarnpkg.com/lodash.isplainobject/-/lodash.isplainobject-4.0.6.tgz#7c526a52d89b45c45cc690b88163be0497f550cb"
-  integrity sha1-fFJqUtibRcRcxpC4gWO+BJf1UMs=
-
-lodash.isstring@^4.0.1:
-  version "4.0.1"
-  resolved "https://registry.yarnpkg.com/lodash.isstring/-/lodash.isstring-4.0.1.tgz#d527dfb5456eca7cc9bb95d5daeaf88ba54a5451"
-  integrity sha1-1SfftUVuynzJu5XV2ur4i6VKVFE=
-
-lodash.mergewith@^4.6.1:
-  version "4.6.1"
-  resolved "https://registry.yarnpkg.com/lodash.mergewith/-/lodash.mergewith-4.6.1.tgz#639057e726c3afbdb3e7d42741caa8d6e4335927"
-  integrity sha512-eWw5r+PYICtEBgrBE5hhlT6aAa75f411bgDz/ZL2KZqYV03USvucsxcHUIlGTDTECs1eunpI7HOV7U+WLDvNdQ==
-
 lodash@^4.1.1, lodash@^4.13.1, lodash@^4.17.10, lodash@^4.17.11, lodash@^4.17.4, lodash@^4.2.1:
   version "4.17.11"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.11.tgz#b39ea6229ef607ecd89e2c8df12536891cac9b8d"
@@ -5195,6 +5240,11 @@ nan@^2.12.1:
   resolved "https://registry.yarnpkg.com/nan/-/nan-2.13.2.tgz#f51dc7ae66ba7d5d55e1e6d4d8092e802c9aefe7"
   integrity sha512-TghvYc72wlMGMVMluVo9WRJc0mB8KxxF/gZ4YYFy7V2ZQX9l7rgbPg7vjS9mt6U5HXODVFVI2bOduCzwOMv/lw==
 
+nanoid@^3.1.22:
+  version "3.1.22"
+  resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-3.1.22.tgz#b35f8fb7d151990a8aebd5aa5015c03cf726f844"
+  integrity sha512-/2ZUaJX2ANuLtTvqTlgqBQNJoQO398KyJgZloL0PZkC0dpysjncRUPsFe3DUPzz/y3h+u7C46np8RMuvF3jsSQ==
+
 nanomatch@^1.2.9:
   version "1.2.13"
   resolved "https://registry.yarnpkg.com/nanomatch/-/nanomatch-1.2.13.tgz#b87a8aa4fc0de8fe6be88895b38983ff265bd119"
@@ -5676,6 +5726,11 @@ parse-passwd@^1.0.0:
   resolved "https://registry.yarnpkg.com/parse-passwd/-/parse-passwd-1.0.0.tgz#6d5b934a456993b23d37f40a382d6f1666a8e5c6"
   integrity sha1-bVuTSkVpk7I9N/QKOC1vFmao5cY=
 
+parse-srcset@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/parse-srcset/-/parse-srcset-1.0.2.tgz#f2bd221f6cc970a938d88556abc589caaaa2bde1"
+  integrity sha1-8r0iH2zJcKk42IVWq8WJyqqiveE=
+
 parseqs@0.0.5:
   version "0.0.5"
   resolved "https://registry.yarnpkg.com/parseqs/-/parseqs-0.0.5.tgz#d5208a3738e46766e291ba2ea173684921a8b89d"
@@ -5901,7 +5956,7 @@ postcss-value-parser@^3.3.0, postcss-value-parser@^3.3.1:
   resolved "https://registry.yarnpkg.com/postcss-value-parser/-/postcss-value-parser-3.3.1.tgz#9ff822547e2893213cf1c30efa51ac5fd1ba8281"
   integrity sha512-pISE66AbVkp4fDQ7VHBwRNXzAAKJjw4Vw7nWI/+Q3vuly7SNfgYXvm6i5IgFylHGK5sP/xHAbB7N49OS4gWNyQ==
 
-postcss@^7.0.0, postcss@^7.0.1, postcss@^7.0.13, postcss@^7.0.14, postcss@^7.0.2, postcss@^7.0.5, postcss@^7.0.7:
+postcss@^7.0.0, postcss@^7.0.1, postcss@^7.0.13, postcss@^7.0.14, postcss@^7.0.2, postcss@^7.0.7:
   version "7.0.14"
   resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.14.tgz#4527ed6b1ca0d82c53ce5ec1a2041c2346bbd6e5"
   integrity sha512-NsbD6XUUMZvBxtQAJuWDJeeC4QFsmWsfozWxCJPWf3M55K9iu2iMDaKqyoOdTJ1R4usBXuxlVFAIo8rZPQD4Bg==
@@ -5910,6 +5965,15 @@ postcss@^7.0.0, postcss@^7.0.1, postcss@^7.0.13, postcss@^7.0.14, postcss@^7.0.2
     source-map "^0.6.1"
     supports-color "^6.1.0"
 
+postcss@^8.0.2:
+  version "8.2.14"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.2.14.tgz#dcf313eb8247b3ce8078d048c0e8262ca565ad2b"
+  integrity sha512-+jD0ZijcvyCqPQo/m/CW0UcARpdFylq04of+Q7RKX6f/Tu+dvpUI/9Sp81+i6/vJThnOBX09Quw0ZLOVwpzX3w==
+  dependencies:
+    colorette "^1.2.2"
+    nanoid "^3.1.22"
+    source-map "^0.6.1"
+
 prelude-ls@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"
@@ -6647,21 +6711,18 @@ samsam@1.3.0:
   resolved "https://registry.yarnpkg.com/samsam/-/samsam-1.3.0.tgz#8d1d9350e25622da30de3e44ba692b5221ab7c50"
   integrity sha512-1HwIYD/8UlOtFS3QO3w7ey+SdSDFE4HRNLZoZRYVQefrOY3l17epswImeB1ijgJFQJodIaHcwkp3r/myBjFVbg==
 
-sanitize-html@^1.18.4:
-  version "1.20.1"
-  resolved "https://registry.yarnpkg.com/sanitize-html/-/sanitize-html-1.20.1.tgz#f6effdf55dd398807171215a62bfc21811bacf85"
-  integrity sha512-txnH8TQjaQvg2Q0HY06G6CDJLVYCpbnxrdO0WN8gjCKaU5J0KbyGYhZxx5QJg3WLZ1lB7XU9kDkfrCXUozqptA==
+sanitize-html@^2.3.2:
+  version "2.3.2"
+  resolved "https://registry.yarnpkg.com/sanitize-html/-/sanitize-html-2.3.2.tgz#a1954aea877a096c408aca7b0c260bef6e4fc402"
+  integrity sha512-p7neuskvC8pSurUjdVmbWPXmc9A4+QpOXIL+4gwFC+av5h+lYCXFT8uEneqsFQg/wEA1IH+cKQA60AaQI6p3cg==
   dependencies:
-    chalk "^2.4.1"
-    htmlparser2 "^3.10.0"
-    lodash.clonedeep "^4.5.0"
-    lodash.escaperegexp "^4.1.2"
-    lodash.isplainobject "^4.0.6"
-    lodash.isstring "^4.0.1"
-    lodash.mergewith "^4.6.1"
-    postcss "^7.0.5"
-    srcset "^1.0.0"
-    xtend "^4.0.1"
+    deepmerge "^4.2.2"
+    escape-string-regexp "^4.0.0"
+    htmlparser2 "^6.0.0"
+    is-plain-object "^5.0.0"
+    klona "^2.0.3"
+    parse-srcset "^1.0.2"
+    postcss "^8.0.2"
 
 sax@^1.2.4:
   version "1.2.4"
@@ -7062,14 +7123,6 @@ sprintf-js@~1.0.2:
   resolved "https://registry.yarnpkg.com/sprintf-js/-/sprintf-js-1.0.3.tgz#04e6926f662895354f3dd015203633b857297e2c"
   integrity sha1-BOaSb2YolTVPPdAVIDYzuFcpfiw=
 
-srcset@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/srcset/-/srcset-1.0.0.tgz#a5669de12b42f3b1d5e83ed03c71046fc48f41ef"
-  integrity sha1-pWad4StC87HV6D7QPHEEb8SPQe8=
-  dependencies:
-    array-uniq "^1.0.2"
-    number-is-nan "^1.0.0"
-
 sshpk@^1.7.0:
   version "1.16.1"
   resolved "https://registry.yarnpkg.com/sshpk/-/sshpk-1.16.1.tgz#fb661c0bef29b39db40769ee39fa70093d6f6877"