CVE-2026-126066
Description
A flaw was found in fast-xml-parser. When the stopNodes configuration option is enabled, the parser repeatedly rescans remaining input when encountering unterminated tag fragments. A remote attacker could exploit this vulnerability by supplying specially crafted XML input containing numerous unclosed tags, consuming excessive CPU resources and causing a Denial of Service (DoS).
Statement
This flaw is rated as a Low severity vulnerability because triggering it requires a specific, non-default configuration in consuming applications and results only in temporary CPU exhaustion without impacting data confidentiality or integrity. Under default parsing configurations across Red Hat environments, the affected stop-node processing routine is inactive, meaning typical workloads are not exposed to the condition. Applications are only susceptible if they explicitly activate stop-node parsing and process unvalidated XML payloads from untrusted sources.
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 | 3.7 | N/A | 3.7 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| 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 | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU)
Frequently Asked Questions
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