CVE-2026-33176
Description
A flaw was found in Active Support, a toolkit of support libraries for Ruby on Rails. A remote attacker can exploit this vulnerability by providing specially crafted strings containing scientific notation (e.g., "1e10000") to number helpers. This input causes the BigDecimal component to expand into extremely large decimal representations, consuming excessive memory and CPU resources. This can lead to a Denial of Service (DoS) vulnerability, making the affected system unavailable.
Statement
This flaw is rated as Moderate by Red Hat. Successful exploitation of this vulnerability requires an attacker to reach the vulnerable code path within the Active Support library as used by the hosting application. Because this functionality is not typically exposed directly to unauthenticated users, an attacker would generally need at least low-privileged (authenticated) access to the application to trigger the issue.
Mitigation
To mitigate this issue, applications that use Active Support number helpers to process untrusted input should implement strict input validation. This involves sanitizing or restricting the format and length of numerical strings before they are passed to Active Support, thereby preventing the `BigDecimal` component from expanding into extremely large decimal representations and consuming excessive resources.
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 | 6.5 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Frequently Asked Questions
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