Mathematical Foundations of Poisoning Attacks on Linear Regression over Cumulative Distribution Functions

Fuente: arXiv
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Main Authors: Sato, Atsuki, Aumüller, Martin, Matsui, Yusuke
Format: Preprint
Published: 2026
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author Sato, Atsuki
Aumüller, Martin
Matsui, Yusuke
author_facet Sato, Atsuki
Aumüller, Martin
Matsui, Yusuke
contents Learned indexes are a class of index data structures that enable fast search by approximating the cumulative distribution function (CDF) using machine learning models (Kraska et al., SIGMOD'18). However, recent studies have shown that learned indexes are vulnerable to poisoning attacks, where injecting a small number of poison keys into the training data can significantly degrade model accuracy and reduce index performance (Kornaropoulos et al., SIGMOD'22). In this work, we provide a rigorous theoretical analysis of poisoning attacks targeting linear regression models over CDFs, one of the most basic regression models and a core component in many learned indexes. Our main contributions are as follows: (i) We present a theoretical proof characterizing the optimal single-point poisoning attack and show that the existing method yields the optimal attack. (ii) We show that in multi-point attacks, the existing greedy approach is not always optimal, and we rigorously derive the key properties that an optimal attack should satisfy. (iii) We propose a method to compute an upper bound of the multi-point poisoning attack's impact and empirically demonstrate that the loss under the greedy approach is often close to this bound. Our study deepens the theoretical understanding of attack strategies against linear regression models on CDFs and provides a foundation for the theoretical evaluation of attacks and defenses on learned indexes.
format Preprint
id arxiv_https___arxiv_org_abs_2603_00537
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Mathematical Foundations of Poisoning Attacks on Linear Regression over Cumulative Distribution Functions
Sato, Atsuki
Aumüller, Martin
Matsui, Yusuke
Machine Learning
Databases
Learned indexes are a class of index data structures that enable fast search by approximating the cumulative distribution function (CDF) using machine learning models (Kraska et al., SIGMOD'18). However, recent studies have shown that learned indexes are vulnerable to poisoning attacks, where injecting a small number of poison keys into the training data can significantly degrade model accuracy and reduce index performance (Kornaropoulos et al., SIGMOD'22). In this work, we provide a rigorous theoretical analysis of poisoning attacks targeting linear regression models over CDFs, one of the most basic regression models and a core component in many learned indexes. Our main contributions are as follows: (i) We present a theoretical proof characterizing the optimal single-point poisoning attack and show that the existing method yields the optimal attack. (ii) We show that in multi-point attacks, the existing greedy approach is not always optimal, and we rigorously derive the key properties that an optimal attack should satisfy. (iii) We propose a method to compute an upper bound of the multi-point poisoning attack's impact and empirically demonstrate that the loss under the greedy approach is often close to this bound. Our study deepens the theoretical understanding of attack strategies against linear regression models on CDFs and provides a foundation for the theoretical evaluation of attacks and defenses on learned indexes.
title Mathematical Foundations of Poisoning Attacks on Linear Regression over Cumulative Distribution Functions
topic Machine Learning
Databases
url https://arxiv.org/abs/2603.00537