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The vulnerability stems from uncontrolled resource consumption during XML parsing, specifically classified under CWE-400 for resource exhaustion and denial of service.
When parsing untrusted XML documents, standard parsers fail to limit attribute counts, attribute sizes, comment lengths, and tag name sizes.
Attackers exploit this by injecting thousands of redundant attributes into a single XML element, forcing the underlying hash table implementation into worst-case collision behavior.
This quadratic hash table collision causes CPU utilization to spike to maximum capacity, effectively stalling the application thread.
Additionally, giant attribute value bombs allocate megabytes of memory per single attribute, leading to rapid memory exhaustion and out-of-memory crashes.
Comment amplification and tag name memory bombs further strain symbol tables and streaming buffers, bypassing basic validation checks.
Parameter entity expansion and embedded null bytes in identifiers exacerbate the attack surface, allowing C-string truncation bypasses in downstream systems.
Because Python’s standard library and older defusedxml packages lacked robust structural limits against modern multi-vector XML payloads, applications remained exposed.
The of SafeXML integrates a high-performance Rust parsing engine via PyO3 to enforce strict hard limits across all parsing vectors.
These include max_attributes defaults, max_attribute_size boundaries, and GIL-free multi-core request handling to maintain service availability under heavy load.
DailyCVE Form:
Platform: Python SafeXML Library
Version: v1.0.1 Release
Vulnerability: Resource Exhaustion DoS
Severity: Critical Threat Level
date: October 11 2026
Prediction: Patched In v1.0.1
What Undercode Say:
Analytics
Usage statistics demonstrate that switching to SafeXML provides a 1.63x single-threaded throughput boost and 1.43x multi-threaded concurrency improvement while blocking memory corruption and hash collision attacks.
Bash Commands and Codes
pip install safexml
pytest –cov-fail-under=100
python -c “import safexml; safexml.fromstring(”)”
Exploit: (Educational Purposes!)
An attacker crafts an XML payload containing thousands of colliding attributes or oversized comment streams to induce excessive CPU consumption and memory exhaustion.
Example snippet:
&bomb;
Protection: from this CVE
Upgrade to SafeXML version 1.0.1 or higher which enforces strict limits on attribute counts, attribute sizes, comment amplification, name sizes, and parameter entities.
Impact:
Complete service downtime, server memory exhaustion, CPU pinning through hash collisions, and potential downstream database query manipulation via null byte injection.
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Sources:
Reported By: github.com
Extra Source Hub:
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