WordPress before 7.1.4 matched the whitespace inside block comment delimiters () with the regex class s, which accepts a different set of characters in the server-side PHP block parser (PCRE, which includes the vertical tab) than in the block editor JavaScript parser (which includes NBSP and other Unicode spaces). A Contributor could store a delimiter that the server treats as a plain HTML comment, so its block attributes skip the server-side KSES filtering, while the block editor parses it as a real block when an administrator opens the post, running script in the administrator session. Version 7.1.4 accepts only HTML whitespace (space, tab, form feed, carriage return, line feed) in block delimiters in both parsers.
This vulnerability affects the following application versions:
- WordPress 5.0
- WordPress 5.0.1
- WordPress 5.0.2
- WordPress 5.0.3
- WordPress 5.0.4
- WordPress 5.0.6
- WordPress 5.0.7
- WordPress 5.0.8
- WordPress 5.0.9
- WordPress 5.0.10
- WordPress 5.0.11
- WordPress 5.0.12
- WordPress 5.0.13
- WordPress 5.0.14
- WordPress 5.0.15
- WordPress 5.0.16
- WordPress 5.0.17
- WordPress 5.0.18
- WordPress 5.0.19
- WordPress 5.0.20
- WordPress 5.0.21
- WordPress 5.0.22
- WordPress 5.0.23
- WordPress 5.0.24
- WordPress 5.0.25
- WordPress 5.0.26
- WordPress 5.0.27
- WordPress 5.0.28
- WordPress 5.0.29
- WordPress 5.0.30
- WordPress 5.0 Beta 1
- WordPress 5.0 Beta 2
- WordPress 5.0 Beta 3
- WordPress 5.0 Beta 4
- WordPress 5.0 RC1
- WordPress 5.0 RC2
- WordPress 5.0 RC3
- WordPress 5.1
- WordPress 5.1.1
- WordPress 5.1.10
- WordPress 5.1.11
- WordPress 5.1.12
- WordPress 5.1.13
- WordPress 5.1.14
- WordPress 5.1.15
- WordPress 5.1.16
- WordPress 5.1.17
- WordPress 5.1.18
- WordPress 5.1.19
- WordPress 5.1.2
- WordPress 5.1.20
- WordPress 5.1.21
- WordPress 5.1.22
- WordPress 5.1.23
- WordPress 5.1.24
- WordPress 5.1.25
- WordPress 5.1.26
- WordPress 5.1.27
- WordPress 5.1.3
- WordPress 5.1.4
- WordPress 5.1.5
- WordPress 5.1.6
- WordPress 5.1.7
- WordPress 5.1.8
- WordPress 5.1.9
- WordPress 5.2
- WordPress 5.2.1
- WordPress 5.2.10
- WordPress 5.2.11
- WordPress 5.2.12
- WordPress 5.2.13
- WordPress 5.2.14
- WordPress 5.2.15
- WordPress 5.2.16
- WordPress 5.2.17
- WordPress 5.2.18
- WordPress 5.2.19
- WordPress 5.2.2
- WordPress 5.2.20
- WordPress 5.2.21
- WordPress 5.2.22
- WordPress 5.2.23
- WordPress 5.2.24
- WordPress 5.2.25
- WordPress 5.2.26
- WordPress 5.2.27
- WordPress 5.2.28
- WordPress 5.2.29
- WordPress 5.2.3
- WordPress 5.2.4
- WordPress 5.2.5
- WordPress 5.2.6
- WordPress 5.2.7
- WordPress 5.2.8
- WordPress 5.2.9
- WordPress 5.2 Beta 1
- WordPress 5.2 Beta 2
- WordPress 5.3
- WordPress 5.3.1
- WordPress 5.3.10
- WordPress 5.3.11
- WordPress 5.3.12
- WordPress 5.3.13
- WordPress 5.3.14
- WordPress 5.3.15
- WordPress 5.3.16
- WordPress 5.3.17
- WordPress 5.3.18
- WordPress 5.3.19
- WordPress 5.3.2
- WordPress 5.3.20
- WordPress 5.3.21
- WordPress 5.3.22
- WordPress 5.3.23
- WordPress 5.3.24
- WordPress 5.3.25
- WordPress 5.3.26
- WordPress 5.3.3
- WordPress 5.3.4
- WordPress 5.3.5
- WordPress 5.3.6
- WordPress 5.3.7
- WordPress 5.3.8
- WordPress 5.3.9
- WordPress 5.4
- WordPress 5.4.1
- WordPress 5.4.10
- WordPress 5.4.11
- WordPress 5.4.12
- WordPress 5.4.13
- WordPress 5.4.14
- WordPress 5.4.15
- WordPress 5.4.16
- WordPress 5.4.17
- WordPress 5.4.18
- WordPress 5.4.19
- WordPress 5.4.2
- WordPress 5.4.20
- WordPress 5.4.21
- WordPress 5.4.22
- WordPress 5.4.23
- WordPress 5.4.24
- WordPress 5.4.3
- WordPress 5.4.4
- WordPress 5.4.5
- WordPress 5.4.6
- WordPress 5.4.7
- WordPress 5.4.8
- WordPress 5.4.9
- WordPress 5.5
- WordPress 5.5.1
- WordPress 5.5.10
- WordPress 5.5.11
- WordPress 5.5.12
- WordPress 5.5.13
- WordPress 5.5.14
- WordPress 5.5.15
- WordPress 5.5.16
- WordPress 5.5.17
- WordPress 5.5.18
- WordPress 5.5.19
- WordPress 5.5.2
- WordPress 5.5.20
- WordPress 5.5.21
- WordPress 5.5.22
- WordPress 5.5.23
- WordPress 5.5.3
- WordPress 5.5.4
- WordPress 5.5.5
- WordPress 5.5.6
- WordPress 5.5.7
- WordPress 5.5.8
- WordPress 5.5.9
- WordPress 5.6
- WordPress 5.6.1
- WordPress 5.6.10
- WordPress 5.6.11
- WordPress 5.6.12
- WordPress 5.6.13
- WordPress 5.6.14
- WordPress 5.6.15
- WordPress 5.6.16
- WordPress 5.6.17
- WordPress 5.6.18
- WordPress 5.6.19
- WordPress 5.6.2
- WordPress 5.6.20
- WordPress 5.6.21
- WordPress 5.6.22
- WordPress 5.6.3
- WordPress 5.6.4
- WordPress 5.6.5
- WordPress 5.6.6
- WordPress 5.6.7
- WordPress 5.6.8
- WordPress 5.6.9
- WordPress 5.7
- WordPress 5.7.1
- WordPress 5.7.10
- WordPress 5.7.11
- WordPress 5.7.12
- WordPress 5.7.13
- WordPress 5.7.14
- WordPress 5.7.15
- WordPress 5.7.16
- WordPress 5.7.17
- WordPress 5.7.18
- WordPress 5.7.19
- WordPress 5.7.2
- WordPress 5.7.20
- WordPress 5.7.3
- WordPress 5.7.4
- WordPress 5.7.5
- WordPress 5.7.6
- WordPress 5.7.7
- WordPress 5.7.8
- WordPress 5.7.9
- WordPress 5.8
- WordPress 5.8.1
- WordPress 5.8.10
- WordPress 5.8.11
- WordPress 5.8.12
- WordPress 5.8.13
- WordPress 5.8.14
- WordPress 5.8.15
- WordPress 5.8.16
- WordPress 5.8.17
- WordPress 5.8.18
- WordPress 5.8.2
- WordPress 5.8.3
- WordPress 5.8.4
- WordPress 5.8.5
- WordPress 5.8.6
- WordPress 5.8.7
- WordPress 5.8.8
- WordPress 5.8.9
- WordPress 5.9
- WordPress 5.9.1
- WordPress 5.9.10
- WordPress 5.9.11
- WordPress 5.9.12
- WordPress 5.9.13
- WordPress 5.9.14
- WordPress 5.9.15
- WordPress 5.9.16
- WordPress 5.9.17
- WordPress 5.9.18
- WordPress 5.9.19
- WordPress 5.9.2
- WordPress 5.9.3
- WordPress 5.9.4
- WordPress 5.9.5
- WordPress 5.9.6
- WordPress 5.9.7
- WordPress 5.9.8
- WordPress 5.9.9
- WordPress 6.0
- WordPress 6.0.1
- WordPress 6.0.10
- WordPress 6.0.11
- WordPress 6.0.12
- WordPress 6.0.13
- WordPress 6.0.14
- WordPress 6.0.15
- WordPress 6.0.16
- WordPress 6.0.17
- WordPress 6.0.2
- WordPress 6.0.3
- WordPress 6.0.4
- WordPress 6.0.5
- WordPress 6.0.6
- WordPress 6.0.7
- WordPress 6.0.8
- WordPress 6.0.9
- WordPress 6.1
- WordPress 6.1.1
- WordPress 6.1.10
- WordPress 6.1.11
- WordPress 6.1.12
- WordPress 6.1.13
- WordPress 6.1.14
- WordPress 6.1.15
- WordPress 6.1.2
- WordPress 6.1.3
- WordPress 6.1.4
- WordPress 6.1.5
- WordPress 6.1.6
- WordPress 6.1.7
- WordPress 6.1.8
- WordPress 6.1.9
- WordPress 6.2
- WordPress 6.2.1
- WordPress 6.2.10
- WordPress 6.2.11
- WordPress 6.2.12
- WordPress 6.2.13
- WordPress 6.2.14
- WordPress 6.2.2
- WordPress 6.2.3
- WordPress 6.2.4
- WordPress 6.2.5
- WordPress 6.2.6
- WordPress 6.2.7
- WordPress 6.2.8
- WordPress 6.2.9
- WordPress 6.3
- WordPress 6.3.1
- WordPress 6.3.10
- WordPress 6.3.11
- WordPress 6.3.12
- WordPress 6.3.13
- WordPress 6.3.2
- WordPress 6.3.3
- WordPress 6.3.4
- WordPress 6.3.5
- WordPress 6.3.6
- WordPress 6.3.7
- WordPress 6.3.8
- WordPress 6.3.9
- WordPress 6.4
- WordPress 6.4.1
- WordPress 6.4.10
- WordPress 6.4.11
- WordPress 6.4.12
- WordPress 6.4.13
- WordPress 6.4.2
- WordPress 6.4.3
- WordPress 6.4.4
- WordPress 6.4.5
- WordPress 6.4.6
- WordPress 6.4.7
- WordPress 6.4.8
- WordPress 6.4.9
- WordPress 6.5
- WordPress 6.5.10
- WordPress 6.5.11
- WordPress 6.5.12
- WordPress 6.5.13
- WordPress 6.5.2
- WordPress 6.5.3
- WordPress 6.5.4
- WordPress 6.5.5
- WordPress 6.5.6
- WordPress 6.5.7
- WordPress 6.5.8
- WordPress 6.5.9
- WordPress 6.6
- WordPress 6.6.1
- WordPress 6.6.10
- WordPress 6.6.2
- WordPress 6.6.3
- WordPress 6.6.4
- WordPress 6.6.5
- WordPress 6.6.6
- WordPress 6.6.7
- WordPress 6.6.8
- WordPress 6.6.9
- WordPress 6.7
- WordPress 6.7.1
- WordPress 6.7.10
- WordPress 6.7.2
- WordPress 6.7.3
- WordPress 6.7.4
- WordPress 6.7.5
- WordPress 6.7.6
- WordPress 6.7.7
- WordPress 6.7.8
- WordPress 6.7.9
- WordPress 6.8
- WordPress 6.8.1
- WordPress 6.8.10
- WordPress 6.8.11
- WordPress 6.8.2
- WordPress 6.8.3
- WordPress 6.8.4
- WordPress 6.8.5
- WordPress 6.8.6
- WordPress 6.8.7
- WordPress 6.8.8
- WordPress 6.8.9
- WordPress 6.9
- WordPress 6.9.1
- WordPress 6.9.10
- WordPress 6.9.2
- WordPress 6.9.3
- WordPress 6.9.4
- WordPress 6.9.5
- WordPress 6.9.6
- WordPress 6.9.7
- WordPress 6.9.8
- WordPress 6.9.9
- WordPress 7.0
- WordPress 7.0.1
- WordPress 7.0.2
- WordPress 7.0.3
- WordPress 7.0.4
- WordPress 7.0.5
- WordPress 7.0.6
- WordPress 7.0.7
- WordPress 7.1
- WordPress 7.1.1
- WordPress 7.1.2
- WordPress 7.1.3