SecPRBench tested eight frontier models on 265 real bug-introducing commits from Firefox, V8 and OpenSSL: recall ranged from 32.5% to 78.1%, and Codex Security lowered recall 8.3 points while Anthropic's Defending Code raised it 7.7
AspireAI community · arXiv
SecPRBench is the first benchmark built from validated real-world bug-introducing commits rather than from the later fixes, harvested and validated by an automated agentic pipeline across nine critical systems. An LLM judge credits a finding only when it matches the ground-truth vulnerability's root cause. Recall across eight frontier models ranged from 32.5% to 78.1%, with Grok 4.6 and GPT-6 at the top, and in 68% of misses the agent pointed at the right file but argued for the wrong mechanism, so misses are not simply oversights. Security-focused harnesses behaved differently from one another: OpenAI's Codex Security lowered recall by 8.3 points mostly by abstaining, while Anthropic's Defending Code harness raised it by 7.7 points at higher cost. The benchmark and results site are public, but the judging layer is an LLM-as-a-judge, which is the paper's main soft spot.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.