CVE-2026-115775
説明
A flaw was found in Twisted. An unauthenticated remote attacker can cause a Denial of Service (DoS) by exhausting server memory. The issue occurs because the XML stream parser retains unfinished elements in memory without enforcing size or element count limits. By transmitting a continuous stream of child elements within an unclosed container during pre-authentication communication, an attacker can crash the server process.
詳細
Red Hat rates this vulnerability as Important because an unauthenticated remote attacker can cause complete service termination through unbounded memory consumption over a single network connection without requiring credentials. Exposure requires an application to actively process untrusted network traffic through Twisted's XML streaming components, such as in XMPP server implementations. Supported Red Hat products, including Red Hat Ansible Automation Platform, do not utilize or expose this specific XML stream parsing functionality in default operational configurations.
軽減策
--- CME Mitigation Guidance (2026-11-02) ---
Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.
The highest-value action is to enforce strict stanza byte-size and element-count limits within twisted.words.xish.domish XML stream parsers to prevent unbounded in-memory tree accumulation: upgrade to Twisted 26.10.0rc1 (or the fixed Python Twisted/Python3X Twisted/Ansible Automation Platform 25/Lightspeed Rhel/Python3.11 Twisted/Python3.12 Twisted/Ansible Automation Platform 24/Controller Rhel/Ansible Automation Platform 25/Controller Rhel/Ansible Automation Platform 26/Controller Rhel/Ansible Automation Platform 26/Eda Controller Rhel/Ansible Automation Platform 27/Eda Controller Rhel/Automation Controller/Ansible Automation Platform 27/Controller Rhel/Ansible Automation Platform 26/Lightspeed Rhel/Ansible Automation Platform 27/Lightspeed Rhel/Ansible Ai Connect Service builds), which enforce maximum stanza byte size and element count thresholds on XML element streams and raise a ParserError when exceeded, closing all 2 injection vectors (continuous streaming of child elements inside an unclosed container element, streaming oversized byte payloads into an unclosed stanza). Until patched, this is a concern on deployments exposing Twisted XML stream parsing components such as XMPP servers to untrusted network traffic, so restrict network access to endpoints exposing unauthenticated Twisted XML stream parsing services and enforce strict ingress network filtering or upstream reverse-proxy payload inspection. As a compensating measure, monitor cgroup memory pressure indicators and PSI events to detect abnormal stanza accumulation before host exhaustion occurs, enforce per-process address space limits using ulimit or prlimit to restrict memory allocation from runaway stanzas, configure systemd WatchdogSec and automatic service restart to recover automatically if memory exhaustion crashes the process, and apply cgroups v2 memory limits to constrain the blast radius of memory exhaustion to the individual container or service unit. These controls limit blast radius and contain exploitation, but they do not fix the underlying unbounded XML stanza memory accumulation defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-1010 cgroup Memory Pressure Monitoring (memory.events / PSI) (medium)
CVSS (Common Vulnerability Scoring System) のスコアの詳細
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).
以下の CSVV メトリクスおよびスコアは予備的で、再検討の対象となります。
CVSS v3 スコアの内訳
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| ベーススコア | 7.5 | N/A | N/A |
| 攻撃ベクトル | Network | N/A | N/A |
| 攻撃の複雑さ | Low | N/A | N/A |
| 必要な権限 | None | N/A | N/A |
| ユーザー関与レベル | None | N/A | N/A |
| 範囲 | Unchanged | N/A | N/A |
| 機密性 | None | N/A | N/A |
| 完全性への影響 | None | N/A | N/A |
| 可用性への影響 | High | N/A | N/A |
ベクトル
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
脆弱性の原因 (CWE) の理解
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.
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