CVE-2020-6802

In Mozilla Bleach before 3.11, a mutation XSS affects users calling bleach.clean with noscript and a raw tag in the allowed/whitelisted tags option.

Impact

A mutation XSS affects users calling bleach.clean with noscript and a raw tag (see below) in the allowed/whitelisted tags option.

Patches

v3.1.1

Workarounds

• modify bleach.clean calls to not whitelist noscript and one or more of the following raw tags:

title
textarea
script
style
noembed
noframes
iframe
xmp

• A strong Content-Security-Policy without unsafe-inline and unsafe-eval script-srcs) will also help mitigate the risk.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1615315
• https://cure53.de/fp170.pdf
• https://nvd.nist.gov/vuln/detail/CVE-2020-6802
• https://www.checkmarx.com/blog/vulnerabilities-discovered-in-mozilla-bleach

Credits

• Reported by Yaniv Nizry from the CxSCA AppSec group at Checkmarx

For more information

If you have any questions or comments about this advisory:

• Open an issue at https://github.com/mozilla/bleach/issues
• Email us at [email protected]

In Mozilla Bleach before 3.11, a mutation XSS affects users calling bleach.clean with noscript and a raw tag in the allowed/whitelisted tags option.

The updated packages fix a security vulnerability:

Mutation XSS in bleach.clean when noscript and raw tag whitelisted. (CVE-2020-6802)

This update for python-bleach to version 3.1.1 fixes the following issue:

• Python-bleach was updated to 3.1.1
• CVE-2020-6802: Fixed mutation XSS vulnerabilities (boo#1165303).

This update for python-bleach to version 3.1.1 fixes the following issue:

• Python-bleach was updated to 3.1.1
• CVE-2020-6802: Fixed mutation XSS vulnerabilities (boo#1165303).

This update was imported from the openSUSE:Leap:15.1:Update update project.

These are all security issues fixed in the python36-bleach-3.3.0-1.4 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the weblate-4.8.1-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the python310-bleach-6.1.0-1.5 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the python313-bleach-6.4.0-1.1 package on the GA media of openSUSE Tumbleweed.

In Mozilla Bleach before 3.11, a mutation XSS affects users calling bleach.clean with noscript and a raw tag in the allowed/whitelisted tags option.