ghsa-m6xf-fq7q-8743
Vulnerability from github
Published
2020-03-24 15:06
Modified
2024-09-12 20:49
Severity ?
6.1 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.3 (Medium) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
5.3 (Medium) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
VLAI Severity ?
Summary
Bleach vulnerable to mutation XSS via whitelisted math or svg and raw tag
Details
Impact
A mutation XSS affects users calling bleach.clean
with all of:
- the
svg
ormath
in the allowed/whitelisted tags - an RCDATA tag (see below) in the allowed/whitelisted tags
- the keyword argument
strip=False
Patches
Users are encouraged to upgrade to bleach v3.1.2 or greater.
Workarounds
- modify
bleach.clean
calls to usestrip=True
, or not whitelistmath
orsvg
tags and one or more of the following tags:
script
noscript
style
noframes
xmp
noembed
iframe
- A strong Content-Security-Policy without
unsafe-inline
andunsafe-eval
script-src
s) will also help mitigate the risk.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1621692
- https://cure53.de/fp170.pdf
- https://nvd.nist.gov/vuln/detail/CVE-2020-6816
- 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 security@mozilla.org
{ "affected": [ { "package": { "ecosystem": "PyPI", "name": "bleach" }, "ranges": [ { "events": [ { "introduced": "0" }, { "fixed": "3.1.2" } ], "type": "ECOSYSTEM" } ] } ], "aliases": [ "CVE-2020-6816" ], "database_specific": { "cwe_ids": [ "CWE-79" ], "github_reviewed": true, "github_reviewed_at": "2020-03-23T22:25:38Z", "nvd_published_at": "2020-03-24T22:15:00Z", "severity": "MODERATE" }, "details": "### Impact\n\nA [mutation XSS](https://cure53.de/fp170.pdf) affects users calling `bleach.clean` with all of:\n\n* the `svg` or `math` in the allowed/whitelisted tags\n* an RCDATA tag (see below) in the allowed/whitelisted tags\n* the keyword argument `strip=False`\n\n### Patches\n\nUsers are encouraged to upgrade to bleach v3.1.2 or greater.\n\n### Workarounds\n\n* modify `bleach.clean` calls to use `strip=True`, or not whitelist `math` or `svg` tags and one or more of the following tags:\n\n```\nscript\nnoscript\nstyle\nnoframes\nxmp\nnoembed\niframe\n```\n\n* A strong [Content-Security-Policy](https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP) without `unsafe-inline` and `unsafe-eval` [`script-src`s](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src)) will also help mitigate the risk.\n\n### References\n\n* https://bugzilla.mozilla.org/show_bug.cgi?id=1621692\n* https://cure53.de/fp170.pdf\n* https://nvd.nist.gov/vuln/detail/CVE-2020-6816\n* https://www.checkmarx.com/blog/vulnerabilities-discovered-in-mozilla-bleach\n\n### Credits\n\n* Reported by [Yaniv Nizry](https://twitter.com/ynizry) from the CxSCA AppSec group at Checkmarx\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\n* Open an issue at [https://github.com/mozilla/bleach/issues](https://github.com/mozilla/bleach/issues)\n* Email us at [security@mozilla.org](mailto:security@mozilla.org)", "id": "GHSA-m6xf-fq7q-8743", "modified": "2024-09-12T20:49:31Z", "published": "2020-03-24T15:06:32Z", "references": [ { "type": "WEB", "url": "https://github.com/mozilla/bleach/security/advisories/GHSA-m6xf-fq7q-8743" }, { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-6816" }, { "type": "WEB", "url": "https://advisory.checkmarx.net/advisory/CX-2020-4277" }, { "type": "PACKAGE", "url": "https://github.com/mozilla/bleach" }, { "type": "WEB", "url": "https://github.com/mozilla/bleach/releases/tag/v3.1.2" }, { "type": "WEB", "url": "https://github.com/pypa/advisory-database/tree/main/vulns/bleach/PYSEC-2020-28.yaml" }, { "type": "WEB", "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EDQU2SZLZMSSACCBUBJ6NOSRNNBDYFW5" }, { "type": "WEB", "url": "https://www.checkmarx.com/blog/vulnerabilities-discovered-in-mozilla-bleach" } ], "schema_version": "1.4.0", "severity": [ { "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "type": "CVSS_V3" }, { "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N", "type": "CVSS_V4" } ], "summary": "Bleach vulnerable to mutation XSS via whitelisted math or svg and raw tag" }
Loading…
Loading…
Sightings
Author | Source | Type | Date |
---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…