CVE-2026-116695
Description
A flaw was found in Crass. When parsing malformed URL tokens containing escaped backslashes, Crass incorrectly treats the closing parenthesis as escaped, retaining style declarations that web browsers interpret as active Cascading Style Sheets (CSS). A remote attacker could supply crafted CSS to an application relying on Crass for sanitization, enabling unauthorized style injection that can lead to sensitive data exfiltration or user interface manipulation.
Statement
This vulnerability is rated as having Moderate impact because successful exploitation relies on applications accepting untrusted style definitions and passing them through Crass for sanitization, resulting in unauthorized CSS injection rather than direct code or script execution. Because client-side browsers prevent arbitrary script execution from CSS alone, the blast radius is confined to presentation tampering and secondary data leakage via external resources.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.1 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | Required | N/A | N/A |
| Scope | Changed | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | Low | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Unexpected State; Varies by Context
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