Which file

Given a weakness class and a repository, the best of 27 models found the right files at an F1 of 0.229

Cisco’s Foundation AI built 500 tasks from real fixes. In 38.4 per cent of them no model found a correct file, and finding the file did not mean noticing when it was fixed.

38.4%
of 500 tasks where every one of 27 models scored zero at locating the vulnerable file
VLoc Bench, vulnerable snapshot, File F1. The unsolved subset is dominated by large Go and Maven repositories, 47 and 31 per cent of it.

The strongest of 27 language models reaches a File F1 of 0.229 at locating the files behind a named weakness, Cisco’s Foundation AI reports.

The group’s co-authors are at Yale and Carnegie Mellon, and the benchmark covers a task the existing security benchmarks skip: not whether an agent can reproduce or repair a bug it has been shown, but whether it can find where a CWE lives when handed the description and a terminal.

Each of the 500 tasks pairs a repository snapshot from immediately before a real security fix with the one after it, across 290 repositories, six package ecosystems and 147 CWE categories. On the vulnerable snapshot the agent gets the CWE description and read-only terminal access and must name the files. On the patched snapshot it must say the recorded weakness is gone. Four static-analysis tools ran under the same agent interface.

The second task is where the paper’s warning lives. Systems “that identify vulnerable files effectively can still report unsupported locations on patched repositories”, so a good localiser is not a reliable clearer, and a pipeline that trusts the first to stand down after a fix will keep filing findings.

In 38.4 per cent of the 500 tasks every model scores zero, and the authors say more models and larger ones “do not remove this subset”.

What it changes Treat an agent’s list of vulnerable files as a starting point, not a finding. Run it again on the patched tree: if it still names a location, the agent is not measuring the code, and neither is your dashboard.

Primary source read

Who is telling you this

arXiv · primary

Written by
Aman Priyanshu, Supriti Vijay, Kimia Majd and eight others
For
Foundation AI at Cisco Systems, with Yale University and Carnegie Mellon University
What they gain if this is true
The paper’s best guess: Cisco sells security products and a benchmark showing agents fail at this is not against its interest; the tasks and code are published.

Published in the edition of Wednesday, 16 September 2026 · Beat: Science