CVE-2026-115927
Description
A flaw was found in Tornado. When decoding HTTP/1.1 chunked transfer encoding, Tornado processes received data without yielding control back to the event loop. A remote unauthenticated attacker can send requests containing a large volume of small chunks to monopolize the process and consume excessive memory. This issue leads to a Denial of Service (DoS), stalling all other connections handled by the affected process.
Statement
This vulnerability is rated as Moderate because although an unauthenticated remote attacker can trigger a denial of service by stalling the application's event loop and causing substantial memory consumption, the flaw cannot lead to unauthorized data disclosure or system modification. Within Red Hat environments, Tornado is commonly deployed as a backend service behind reverse proxies or within managed container platforms such as OpenShift and OpenStack. The impact is primarily confined to the availability of the specific worker process handling the malicious stream, limiting the overall blast radius across multi-worker architectures.
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 | 5.3 | N/A | 5.3 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | 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 | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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)
When an attacker can directly invoke the blocking code, or the blocking code can be affected by environmental conditions that can be influenced by an attacker, then this can lead to a denial of service by causing unexpected hang or freeze of the code. An unexpected call to blocking code can trigger an infinite loop, or a large loop that causes the software to pause and wait indefinitely.
Frequently Asked Questions
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