# CVE-2018-7753: Bleach URI Scheme Restriction Bypass

Source: https://junglewise.ai/threats/cve-2018-7753-bleach-uri-scheme-restriction-bypass  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2018-03-07  
License: CC BY 4.0 with a link back

CVE-2018-7753 · Severity: low · CVSS 3 · Published 2018-03-07

An issue was discovered in Bleach 2.1.x before 2.1.3. Attributes that have URI values weren't properly sanitized if the values contained character entities. Using character entities, it was possible to construct a URI value with a scheme that was not allowed that would slide through unsanitized.

Technologies: [bleach (PyPI)](https://junglewise.ai/threats/technologies/bleach). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2018-7753 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2018-7753 being exploited in the wild.

**How severe is CVE-2018-7753?** Low severity, with a CVSS score of 3, published 7 March 2018.

**Which products and versions are affected?** bleach (PyPI) ECOSYSTEM:introduced=2.1.0,fixed=2.1.3, GIT:introduced=0,fixed=c5df5789ec3471a31311f42c2d19fc2cf21b35ef|ECOSYSTEM:introduced=2.1,fixed=2.1.3.

**Is there a fix for CVE-2018-7753?** Yes. bleach (PyPI): upgrade to 2.1.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2018-7753?** Check whether you run bleach (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- bleach (PyPI): upgrade to 2.1.3 or later

  ```sh
  pip install "bleach>=2.1.3"
  ```


## Affected products

- bleach (PyPI) ECOSYSTEM:introduced=2.1.0,fixed=2.1.3, GIT:introduced=0,fixed=c5df5789ec3471a31311f42c2d19fc2cf21b35ef|ECOSYSTEM:introduced=2.1,fixed=2.1.3

## Identifiers

- CVE-2018-7753
- GHSA-m9mq-p2f9-cfqv
- PYSEC-2018-51

## Related threats

- [Mozilla Bleach XSS via unsanitized formaction attribute](https://junglewise.ai/threats/mozilla-bleach-xss-via-unsanitized-formaction-attribute-604755fa)
- [Mozilla Bleach ReDoS in linkify with parse_email enabled](https://junglewise.ai/threats/mozilla-bleach-redos-in-linkify-with-parse-email-enabled-47729578)
- [Mozilla Bleach URI sanitization bypass via Unicode characters](https://junglewise.ai/threats/mozilla-bleach-uri-sanitization-bypass-via-unicode-characters-79149728)
- [Cross-site scripting in Bleach](https://junglewise.ai/threats/cve-2021-23980-cross-site-scripting-in-bleach)
- [regular expression denial-of-service (ReDoS) in Bleach](https://junglewise.ai/threats/cve-2020-6817-regular-expression-denial-of-service-redos-in-bleach)