GHSA-486f-hjj9-9vhh CVE-2022-23514
Inefficient Regular Expression Complexity in Loofah
- Severity
- 7.5 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 1.83%
- Chance of exploitation in the next 30 days. Higher than 78.86% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-1333 Inefficient Regular Expression Complexity
- Fix
2.19.1- Upgrade loofah to this version or later
Description
Summary
Loofah < 2.19.1 contains an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.
Mitigation
Upgrade to Loofah >= 2.19.1.
Severity
The Loofah maintainers have evaluated this as High Severity 7.5 (CVSS3.1).
References
- CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
- https://hackerone.com/reports/1684163
Credit
This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).
Affected versions
RubyGems
| Package | Vulnerable | Fixed in |
|---|---|---|
| loofah | < 2.19.1 |
2.19.1 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
loofah RubyGems → 2.19.1
- bundler
bundle update loofah # Gemfile: gem "loofah", ">= 2.19.1"
Severity breakdown
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-1333: Inefficient Regular Expression Complexity
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
How to prevent it
- Architecture and Design: Use regular expressions that do not support backtracking, e.g. by removing nested quantifiers.
- System Configuration: Set backtracking limits in the configuration of the regular expression implementation, such as PHP's pcre.backtrack_limit. Also consider limits on execution time for the process.
- Implementation: Do not use regular expressions with untrusted input. If regular expressions must be used, avoid using backtracking in the expression.
- Implementation: Limit the length of the input that the regular expression will process.
References
Advisories
Packages
Other links
- github.com/flavorjones/loofah/security/advisories/GHSA-486f-hjj9-9vhh
- github.com/flavorjones/loofah/commit/a6e0a1ab90675a17b1b2be189129d94139e4b143
- hackerone.com/reports/1684163
- github.com/rubysec/ruby-advisory-db/blob/master/gems/loofah/CVE-2022-23514.yml
- lists.debian.org/debian-lts-announce/2023/09/msg00011.html
- lists.debian.org/debian-lts-announce/2024/09/msg00044.html
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-5qhf-9phg-95m2 Loofah `allowed_uri?` does not detect `javascript:` URIs split by numeric character references without semicolons | Low | Also affects loofah |
| GHSA-9wjq-cp2p-hrgf Loofah: SVG `href` attribute bypasses local-reference restriction | Medium | Also affects loofah |
| GHSA-8whx-365g-h9vv Loofah `allowed_uri?` does not detect `javascript:` URIs split by named whitespace character references | Low | Also affects loofah |
| GHSA-2j22-pr5w-6gq8 Loofah has improper detection of disallowed URIs via `allowed_uri?` | Low | Also affects loofah |
| GHSA-46fp-8f5p-pf2m Improper detection of disallowed URIs by Loofah `allowed_uri?` | Low | Also affects loofah |
| GHSA-3x8r-x6xp-q4vm Uncontrolled Recursion in Loofah | High | Also affects loofah |
| GHSA-228g-948r-83gx Improper neutralization of data URIs may allow XSS in Loofah | Medium | Also affects loofah |
| GHSA-c3gv-9cxf-6f57 Loofah Allows Cross-site Scripting | Medium | Also affects loofah |
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