diff --git a/misc/factor.vim.fgen b/misc/factor.vim.fgen
index 75dc4e04c0..3d0e415e4b 100644
--- a/misc/factor.vim.fgen
+++ b/misc/factor.vim.fgen
@@ -151,7 +151,7 @@ syn cluster factorWordOps       contains=factorConstant,factorAlias,factorSingle
 " LIBRARY:
 "#\ "
 
-syn match factorEscape /\\\([\\stnr0e\"]\|u\x\{6}\|u{\S\+}\)/ contained display
+syn match factorEscape /\\\([\\astnr0e\"]\|u\x\{6}\|u{\S\+}\|x\x\{2}\)/ contained display
 syn region factorString start=/\<"/ skip=/\\"/ end=/"/ contains=factorEscape
 syn region factorTriString start=/\<"""/ skip=/\\"/ end=/"""/ contains=factorEscape
 syn region factorSbuf start=/\<[-a-zA-Z0-9]\+"\>/ skip=/\\"/ end=/"/
diff --git a/misc/vim/syntax/factor.vim b/misc/vim/syntax/factor.vim
index 5a0a4f71da..40d556830f 100644
--- a/misc/vim/syntax/factor.vim
+++ b/misc/vim/syntax/factor.vim
@@ -139,7 +139,7 @@ syn cluster factorWordOps       contains=factorConstant,factorAlias,factorSingle
 " LIBRARY:
 "#\ "
 
-syn match factorEscape /\\\([\\stnr0e\"]\|u\x\{6}\|u{\S\+}\)/ contained display
+syn match factorEscape /\\\([\\astnr0e\"]\|u\x\{6}\|u{\S\+}\|x\x\{2}\)/ contained display
 syn region factorString start=/\<"/ skip=/\\"/ end=/"/ contains=factorEscape
 syn region factorTriString start=/\<"""/ skip=/\\"/ end=/"""/ contains=factorEscape
 syn region factorSbuf start=/\<[-a-zA-Z0-9]\+"\>/ skip=/\\"/ end=/"/