Jailbreaking the Matrix: Nullspace Steering for Controlled Model Subversion

Fuente: arXiv
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Auteurs principaux: Pramanik, Vishal, Maliha, Maisha, Jha, Susmit, Jha, Sumit Kumar
Format: Preprint
Publié: 2026
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author Pramanik, Vishal
Maliha, Maisha
Jha, Susmit
Jha, Sumit Kumar
author_facet Pramanik, Vishal
Maliha, Maisha
Jha, Susmit
Jha, Sumit Kumar
contents Large language models remain vulnerable to jailbreak attacks -- inputs designed to bypass safety mechanisms and elicit harmful responses -- despite advances in alignment and instruction tuning. We propose Head-Masked Nullspace Steering (HMNS), a circuit-level intervention that (i) identifies attention heads most causally responsible for a model's default behavior, (ii) suppresses their write paths via targeted column masking, and (iii) injects a perturbation constrained to the orthogonal complement of the muted subspace. HMNS operates in a closed-loop detection-intervention cycle, re-identifying causal heads and reapplying interventions across multiple decoding attempts. Across multiple jailbreak benchmarks, strong safety defenses, and widely used language models, HMNS attains state-of-the-art attack success rates with fewer queries than prior methods. Ablations confirm that nullspace-constrained injection, residual norm scaling, and iterative re-identification are key to its effectiveness. To our knowledge, this is the first jailbreak method to leverage geometry-aware, interpretability-informed interventions, highlighting a new paradigm for controlled model steering and adversarial safety circumvention.
format Preprint
id arxiv_https___arxiv_org_abs_2604_10326
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Jailbreaking the Matrix: Nullspace Steering for Controlled Model Subversion
Pramanik, Vishal
Maliha, Maisha
Jha, Susmit
Jha, Sumit Kumar
Cryptography and Security
Artificial Intelligence
Large language models remain vulnerable to jailbreak attacks -- inputs designed to bypass safety mechanisms and elicit harmful responses -- despite advances in alignment and instruction tuning. We propose Head-Masked Nullspace Steering (HMNS), a circuit-level intervention that (i) identifies attention heads most causally responsible for a model's default behavior, (ii) suppresses their write paths via targeted column masking, and (iii) injects a perturbation constrained to the orthogonal complement of the muted subspace. HMNS operates in a closed-loop detection-intervention cycle, re-identifying causal heads and reapplying interventions across multiple decoding attempts. Across multiple jailbreak benchmarks, strong safety defenses, and widely used language models, HMNS attains state-of-the-art attack success rates with fewer queries than prior methods. Ablations confirm that nullspace-constrained injection, residual norm scaling, and iterative re-identification are key to its effectiveness. To our knowledge, this is the first jailbreak method to leverage geometry-aware, interpretability-informed interventions, highlighting a new paradigm for controlled model steering and adversarial safety circumvention.
title Jailbreaking the Matrix: Nullspace Steering for Controlled Model Subversion
topic Cryptography and Security
Artificial Intelligence
url https://arxiv.org/abs/2604.10326