First published: Tue Aug 10 2021(Updated: )
> ### Meta > * CVSS: `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC` (5.7) ### Problem Failing to properly parse, sanitize and encode malicious rich-text content, the content rendering process in the website frontend is vulnerable to cross-site scripting. Corresponding rendering instructions via TypoScript functionality _[HTMLparser](https://docs.typo3.org/m/typo3/reference-typoscript/10.4/en-us/Functions/Htmlparser.html)_ do not consider all potentially malicious HTML tag & attribute combinations per default. In addition, the lack of comprehensive default node configuration for rich-text fields in the backend user interface fosters this malfunction. In default scenarios, a valid backend user account is needed to exploit this vulnerability. In case custom plugins used in the website frontend accept and reflect rich-text content submitted by users, no authentication is required. ### Solution Update to TYPO3 versions 7.6.53 ELTS, 8.7.42 ELTS, 9.5.29, 10.4.19, 11.3.2 that fix the problem described above. Custom package _[typo3/html-sanitizer](https://github.com/TYPO3/html-sanitizer)_ - based on allow-lists only - takes care of sanitizing potentially malicious markup. The default behavior is based on safe and commonly used markup - however, this can be extended or restricted further in case it is necessary for individual scenarios. During the frontend rendering process, sanitization is applied to the default TypoScript path `lib.parseFunc`, which is implicitly used by the Fluid view-helper instruction `f:format.html`. Rich-text data persisted using the backend user interface is sanitized as well. Implementation details are explained in corresponding [ChangeLog documentation](https://docs.typo3.org/c/typo3/cms-core/master/en-us/Changelog/9.5.x/Important-94484-IntroduceHTMLSanitizer.html). ### Credits Thanks to Benjamin Stiber, Gert-Jan Jansma, Gábor Ács-Kurucz, Alexander Kellner, Richie Lee, Nina Rösch who reported this issue, and to TYPO3 security team member Oliver Hader, as well as TYPO3 contributor Susanne Moog who fixed the issue. ### References * [TYPO3-CORE-SA-2021-013](https://typo3.org/security/advisory/typo3-core-sa-2021-013)
Credit: security-advisories@github.com security-advisories@github.com
Affected Software | Affected Version | How to fix |
---|---|---|
composer/typo3/cms | >=10.0.0<10.4.19>=11.0.0<11.3.2>=9.0.0<9.5.29 | |
composer/typo3/cms-core | >=10.0.0<10.4.19>=11.0.0<11.3.2>=9.0.0<9.5.29 | |
Typo3 Typo3 | >=7.0.0<=7.6.52 | |
Typo3 Typo3 | >=8.0.0<=8.7.41 | |
Typo3 Typo3 | >=9.0.0<=9.5.28 | |
Typo3 Typo3 | >=10.0.0<=10.4.18 | |
Typo3 Typo3 | >=11.0.0<=11.3.1 | |
composer/typo3/cms | >=7.0.0<7.6.53 | 7.6.53 |
composer/typo3/cms | >=8.0.0<8.7.42 | 8.7.42 |
composer/typo3/cms | >=9.0.0<9.5.29 | 9.5.29 |
composer/typo3/cms | >=11.0.0<11.3.2 | 11.3.2 |
composer/typo3/cms | >=10.0.0<10.4.19 | 10.4.19 |
composer/typo3/cms-core | >=9.0.0<9.5.29 | 9.5.29 |
composer/typo3/cms-core | >=11.0.0<11.3.2 | 11.3.2 |
composer/typo3/cms-core | >=10.0.0<10.4.19 | 10.4.19 |
composer/typo3/cms-core | >=8.0.0<8.7.42 | 8.7.42 |
composer/typo3/cms-core | >=7.0.0<7.6.53 | 7.6.53 |
>=7.0.0<=7.6.52 | ||
>=8.0.0<=8.7.41 | ||
>=9.0.0<=9.5.28 | ||
>=10.0.0<=10.4.18 | ||
>=11.0.0<=11.3.1 |
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TYPO3-CORE-SA-2021-013 is a vulnerability in TYPO3 where the content rendering process in the website frontend is vulnerable to cross-site scripting.
TYPO3 versions between 7.0.0 and 7.6.52, 8.0.0 and 8.7.41, 9.0.0 and 9.5.28, 10.0.0 and 10.4.18, and 11.0.0 and 11.3.1 are affected by TYPO3-CORE-SA-2021-013.
TYPO3-CORE-SA-2021-013 has a severity rating of 6.1, which is considered medium.
To fix TYPO3-CORE-SA-2021-013, you should update to TYPO3 versions 7.6.53, 8.7.42, 9.5.29, 10.4.19, or 11.3.2, depending on your installed version.
You can find more information about TYPO3-CORE-SA-2021-013 in the TYPO3 security advisory TYPO3-CORE-SA-2021-013 and in the GitHub security advisory GHSA-c5c9-8c6m-727v.