CVE-2023-36823: Sanitize Cross-Site Scripting Vulnerability

HIGH
Advisory Identifier: GHSA-f5ww-cq3m-q3g7
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CVSS 7.1
CWE-79
Published
Advisory Summary

CVE-2023-36823 is a HIGH (CVSS 7.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Sanitize libraries in the RubyGems ecosystem. The issue involves sanitize vulnerable to cross-site scripting via insufficient neutralization of `style` element content. Remediation is available by upgrading affected packages to version 6.0.2.

CVE-2023-36823 at a Glance

CVE Identifier CVE-2023-36823
GHSA Identifier GHSA-f5ww-cq3m-q3g7
Severity HIGH
CVSS v3.1 Base Score 7.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Sanitize
Package Ecosystem RubyGems
Published Date
Last Updated

Security Impact

CVSS: 7.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2023-36823

To remediate this vulnerability, upgrade all affected Sanitize dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

sanitize fixed: 6.0.2 
Upgrade sanitize to 6.0.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for sanitize

How to Check if You Are Affected

To determine whether your application is affected by CVE-2023-36823, inspect your project dependencies for Sanitize:

inspect dependencies for sanitize

Analyze the terminal output to locate any version of Sanitize in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.0.2), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Sanitize, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact Using carefully crafted input, an attacker may be able to sneak arbitrary HTML and CSS through Sanitize `>= 3.0.0, < 6.0.2` when Sanitize is configured to use the built-in "relaxed" config or when using a custom config that allows `style` elements and one or more CSS at-rules. This could result in XSS (cross-site scripting) or other undesired behavior when the malicious HTML and CSS are rendered in a browser. ### Patches Sanitize `>= 6.0.2` performs additional escaping of CSS in `style` element content, which fixes this issue. ### Workarounds Users who are unable to upgrade can prevent this issue by using a Sanitize config that doesn't allow `style` elements, using a Sanitize config that doesn't allow CSS at-rules, or by manually escaping the character sequence `</` as `<\/` in `style` element content. ### Credit This issue was found by @cure53 during an audit of a project that uses Sanitize and was reported by one of that project's maintainers. Thank you!

CVE-2023-36823 Affected Sanitize Versions

1 component(s)
Fixed Versions:
6.0.2
Product / Package Ecosystem Affected Versions Fixed Version
sanitize
gem/sanitize
RubyGems
≥ 3.0.0
< 6.0.2
6.0.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/rgrove/sanitize/security/advisories/GHSA-f5ww-cq3m-q3g7
NVD — CVE-2023-36823 NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-36823
Security Fix Commit FIX COMMIT
https://github.com/rgrove/sanitize/commit/76ed46e6dc70820f38efe27de8dabd54dddb5220
Sanitize Source Repository REPOSITORY
https://github.com/rgrove/sanitize
Sanitize Release RELEASE
https://github.com/rgrove/sanitize/releases/tag/v6.0.2
Sanitize Source Repository REPOSITORY
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/sanitize/CVE-2023-36823.yml
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2023/11/msg00008.html

Frequently Asked Questions

What is CVE-2023-36823?
CVE-2023-36823 is a security vulnerability in Sanitize involving Sanitize vulnerable to Cross-site Scripting via insufficient neutralization of `style` element content under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Sanitize versions are affected?
Affected versions include releases prior to 6.0.2 across affected packages: sanitize.
What version fixes CVE-2023-36823?
Upgrading to 6.0.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is sanitize affected?
Yes, sanitize is affected in releases prior to 6.0.2. Upgrade your dependency to 6.0.2 or later.
What is the CVSS score of CVE-2023-36823?
CVE-2023-36823 has a CVSS v3.1 base score of 7.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L.
What CWE is associated with CVE-2023-36823?
CVE-2023-36823 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check RubyGems dependencies for CVE-2023-36823?
Run the dependency tree command: 'inspect dependencies for sanitize'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-f5ww-cq3m-q3g7",
  "modified" : "2023-07-06T19:45:44Z",
  "published" : "2023-07-06T19:45:44Z",
  "aliases" : [ "CVE-2023-36823" ],
  "summary" : "Sanitize vulnerable to Cross-site Scripting via insufficient neutralization of `style` element content",
  "details" : "### Impact\n\nUsing carefully crafted input, an attacker may be able to sneak arbitrary HTML and CSS through Sanitize `>= 3.0.0, < 6.0.2` when Sanitize is configured to use the built-in \"relaxed\" config or when using a custom config that allows `style` elements and one or more CSS at-rules. This could result in XSS (cross-site scripting) or other undesired behavior when the malicious HTML and CSS are rendered in a browser.\n\n### Patches\n\nSanitize `>= 6.0.2` performs additional escaping of CSS in `style` element content, which fixes this issue.\n\n### Workarounds\n\nUsers who are unable to upgrade can prevent this issue by using a Sanitize config that doesn't allow `style` elements, using a Sanitize config that doesn't allow CSS at-rules, or by manually escaping the character sequence `</` as `<\\/` in `style` element content.\n\n### Credit\n\nThis issue was found by @cure53 during an audit of a project that uses Sanitize and was reported by one of that project's maintainers. Thank you!",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "sanitize"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0"
      }, {
        "fixed" : "6.0.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/rgrove/sanitize/security/advisories/GHSA-f5ww-cq3m-q3g7"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-36823"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rgrove/sanitize/commit/76ed46e6dc70820f38efe27de8dabd54dddb5220"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rgrove/sanitize"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rgrove/sanitize/releases/tag/v6.0.2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/sanitize/CVE-2023-36823.yml"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2023/11/msg00008.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-07-06T19:45:44Z",
    "nvd_published_at" : "2023-07-06T16:15:10Z"
  }
}