diff --git a/package.json b/package.json
index 3b343b8bb3f3..c490ff7c8adb 100644
--- a/package.json
+++ b/package.json
@@ -69,7 +69,7 @@
     "postcss-less": "3.1.4",
     "postcss-media-query-parser": "0.2.3",
     "postcss-scss": "2.1.1",
-    "postcss-selector-parser": "2.2.3",
+    "postcss-selector-parser": "6.0.11",
     "postcss-values-parser": "2.0.1",
     "regexp-util": "1.2.2",
     "remark-footnotes": "2.0.0",
diff --git a/yarn.lock b/yarn.lock
index a3d88990be38..a71c38bfe621 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2687,6 +2687,11 @@ cspell@4.2.5:
     glob "^7.1.6"
     minimatch "^3.0.4"
 
+cssesc@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/cssesc/-/cssesc-3.0.0.tgz#37741919903b868565e1c09ea747445cd18983ee"
+  integrity sha512-/Tb/JcjK111nNScGob5MNtsntNM1aCNUDipB/TkwZFhyDrrE47SOx/18wF2bbjgc3ZzCSKW1T5nt5EbFoAz/Vg==
+
 cssom@^0.4.4:
   version "0.4.4"
   resolved "https://registry.yarnpkg.com/cssom/-/cssom-0.4.4.tgz#5a66cf93d2d0b661d80bf6a44fb65f5c2e4e0a10"
@@ -3087,8 +3092,7 @@ eslint-plugin-jest@24.1.3:
     "@typescript-eslint/experimental-utils" "^4.0.1"
 
 "eslint-plugin-prettier-internal-rules@link:scripts/tools/eslint-plugin-prettier-internal-rules":
-  version "0.0.0"
-  uid ""
+  version "1.0.3"
 
 eslint-plugin-react@7.22.0:
   version "7.22.0"
@@ -5825,14 +5829,13 @@ postcss-scss@2.1.1:
   dependencies:
     postcss "^7.0.6"
 
-postcss-selector-parser@2.2.3:
-  version "2.2.3"
-  resolved "https://registry.yarnpkg.com/postcss-selector-parser/-/postcss-selector-parser-2.2.3.tgz#f9437788606c3c9acee16ffe8d8b16297f27bb90"
-  integrity sha1-+UN3iGBsPJrO4W/+jYsWKX8nu5A=
+postcss-selector-parser@6.0.11:
+  version "6.0.11"
+  resolved "https://registry.yarnpkg.com/postcss-selector-parser/-/postcss-selector-parser-6.0.11.tgz#2e41dc39b7ad74046e1615185185cd0b17d0c8dc"
+  integrity sha512-zbARubNdogI9j7WY4nQJBiNqQf3sLS3wCP4WfOidu+p28LofJqDH1tcXypGrcmMHhDk2t9wGhCsYe/+szLTy1g==
   dependencies:
-    flatten "^1.0.2"
-    indexes-of "^1.0.1"
-    uniq "^1.0.1"
+    cssesc "^3.0.0"
+    util-deprecate "^1.0.2"
 
 postcss-values-parser@2.0.1:
   version "2.0.1"
@@ -7220,6 +7223,11 @@ use@^3.1.0:
   resolved "https://registry.yarnpkg.com/use/-/use-3.1.1.tgz#d50c8cac79a19fbc20f2911f56eb973f4e10070f"
   integrity sha512-cwESVXlO3url9YWlFW/TA9cshCEhtu7IKJ/p5soJ/gGpj7vbvFrAY/eIioQ6Dw23KjZhYgiIo8HOs1nQ2vr/oQ==
 
+util-deprecate@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/util-deprecate/-/util-deprecate-1.0.2.tgz#450d4dc9fa70de732762fbd2d4a28981419a0ccf"
+  integrity sha512-EPD5q1uXyFxJpCrLnCc1nHnq3gOa6DZBocAIiI2TaSCA7VCJ1UJDMagCzIkXNsUYfD1daK//LTEQ8xiIbrHtcw==
+
 uuid@^3.3.2:
   version "3.4.0"
   resolved "https://registry.yarnpkg.com/uuid/-/uuid-3.4.0.tgz#b23e4358afa8a202fe7a100af1f5f883f02007ee"