Описание
regular expression denial-of-service (ReDoS) in Bleach
Impact
bleach.clean behavior parsing style attributes could result in a regular expression denial of service (ReDoS).
Calls to bleach.clean with an allowed tag with an allowed style attribute are vulnerable to ReDoS. For example, bleach.clean(..., attributes={'a': ['style']}).
Patches
3.1.4
Workarounds
-
do not whitelist the style attribute in
bleach.cleancalls -
limit input string length
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1623633
- https://www.regular-expressions.info/redos.html
- https://blog.r2c.dev/posts/finding-python-redos-bugs-at-scale-using-dlint-and-r2c/
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-6817
Credits
- Reported by schwag09 of r2c
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 security@mozilla.org
Ссылки
- https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm
- https://nvd.nist.gov/vuln/detail/CVE-2020-6817
- https://bugzilla.mozilla.org/show_bug.cgi?id=1623633
- https://github.com/mozilla/bleach/releases/tag/v3.1.4
- https://github.com/pypa/advisory-database/tree/main/vulns/bleach/PYSEC-2020-340.yaml
- https://snyk.io/vuln/SNYK-PYTHON-BLEACH-561754
Пакеты
bleach
< 3.1.4
3.1.4
Связанные уязвимости
bleach.clean behavior parsing style attributes could result in a regular expression denial of service (ReDoS). Calls to bleach.clean with an allowed tag with an allowed style attribute are vulnerable to ReDoS. For example, bleach.clean(..., attributes={'a': ['style']}).
bleach.clean behavior parsing style attributes could result in a regular expression denial of service (ReDoS). Calls to bleach.clean with an allowed tag with an allowed style attribute are vulnerable to ReDoS. For example, bleach.clean(..., attributes={'a': ['style']}).
bleach.clean behavior parsing style attributes could result in a regul ...
