Today · post October 16

Epoch's index puts open models 6-7 months behind on cyber

Epoch AI estimates that open-weight models trail the closed frontier on cyber capabilities by about six to seven months, and the top-scoring open-weight model is Z.ai's GLM-5.3. Epoch AI is a research group that measures trends in AI capability and compute. The Cyber ECI is Epoch's own cyber-capability index. Epoch wrote: "How far behind the closed frontier are open-weight cyber capabilities? About 6–7 months. Zai's GLM-5.3 is the highest-scoring open-weight model on our Cyber ECI. Its score of 160 beats OpenAI's GPT-5.4, released in March." (Epoch AI, 2026-10-16) The October 13 issue's archive pick cited Epoch's estimate of an average seven-month overall gap between US and Chinese models. Today's figure measures only cyber capability, and it compares open-weight models with the closed frontier. AI policy analyst Dean Ball commented: "A 6-month lag today is subjectively larger than a 6-month lag 6 months ago." (Dean Ball, 2026-10-16) Ball's premise is that AI has sped up research, so the same number of months means a larger capability gap. Ball doesn't quantify that premise. His post also says six to nine months, while Epoch's original post says six to seven. How the six to seven months is derived from scores, and the full leaderboard, aren't in Epoch's post. GPT-5.4's score isn't given either. How we checked →

Concept illustration: a beige slope rises from lower left to upper right above a black area, with a large open red-orange laptop at its lower left in front of a pale pink circle, its screen lettered "GLM-5.3" and, on a white strip beside a blue and red Z shape, "Z.AI", and a smaller open pale grey laptop near the upper right. Partway up the slope, below and to the right of a black-bordered sign reading "EPOCH AI CYBER ECI", a crouching person with dark curly hair, dark clothes and white shoes holds a small round dark object beside the red laptop, and a thin line runs from it along the slope toward the grey laptop.

Source and checks

This item ran in the brief of Oct 17, 2026, alongside 15 other items. How we checked it, the quote checks and what was still missing that day are on that issue's How we checked page.

Cite this item

SecondSource (2026). "Epoch's index puts open models 6-7 months behind on cyber." https://secondsource.io/en/research/2026-10-17-1/. Accessed access date.