CVE-2026-86000
Description
A flaw was found in Soup Sieve, a CSS selector library. An attacker can craft a malicious CSS selector that, when processed by the library, leads to excessive CPU consumption. This occurs due to a polynomial-time regular expression denial of service (ReDoS) vulnerability in the selector parser. Successful exploitation can cause the application to stall, leading to a denial of service.
Statement
This is an Moderate denial-of-service flaw in the Soup Sieve library, affecting applications that process untrusted or attacker-controlled CSS selectors. Exploitation can lead to excessive CPU consumption, potentially exhausting application workers and stalling services, which is a significant impact beyond simple resource consumption.
Mitigation
No mitigation is currently available for this vulnerability. Users are advised to apply the security update when available.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | N/A | 5.3 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU)
Attackers can create crafted inputs that intentionally cause the regular expression to use excessive backtracking in a way that causes the CPU consumption to spike.
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