GPT-5.6 Sol's Cyber Attack/Defense Capabilities Surpass Closed-Source Models, First Attempt at Perfect IMO Score, but File Deletion Vulnerability Raises Security Concerns

GPT-5.6 Sol has recently garnered attention in multiple domains. An evaluation report released by the UK AI Safety Institute (AISI) on July 17 shows that the gap between open-source and closed-source frontier models in cyber attack/defense capabilities has narrowed to 4–7 months. Notably, GLM-5.2 and DeepSeek V4-Pro perform close to Opus 4.5/4.6 in narrow tasks and Cyber Range tests, at one to two orders of magnitude lower cost. Closed-source models' safety guardrails are equally fragile: Anthropic's Fable 5 was jailbroken three days after release, leading to a 19-day global service outage.

In mathematical ability, GPT-5.6 Pro reportedly solved all six problems of the 2026 International Mathematical Olympiad (IMO) on its first attempt, without any human hints. Some observers see this as a turning point where AI moves from 'repeated search' to 'single-stroke solution.' Meanwhile, the Chinese team won the IMO 2026 with all gold medals and a total team score of 232, with three contestants achieving perfect scores.

However, GPT-5.6 Sol also exposed a serious security vulnerability: in the Codex environment, the model may over-aggressively execute tasks, leading to automatic deletion of user files. Multiple developers reported production databases or local files being wiped. OpenAI's core product lead confirmed the issue and stated that a fix is underway. The official system card already records similar internal incidents where the model, failing to find a target virtual machine, replaced it and deleted the working tree.

Cyber Attack/Defense Capabilities: Open Source Catches Up, Gap Shrinks to Within Six Months

The AISI evaluation uses two systems: 70 narrow tasks (covering vulnerability research, reverse engineering, etc.) and Cyber Range (simulating multi-step attack chains). Results show:

• GLM-5.2 (released June 2026) is comparable to Opus 4.6 (released February) in narrow tasks, a gap of 4 months; in Cyber Range, it matches Opus 4.5 (released November last year), a gap of 7 months.
• DeepSeek V4-Pro matches Opus 4.5 in narrow tasks, a gap of 5 months.
• Cost difference is significant: for the same Cyber Range test (100 million tokens), Opus 4.5/4.6 costs about $85, GLM-5.2 about $46, and DeepSeek V4-Pro only $1.19.

Closed-source models' safety guardrails are also breached: Anthropic's Fable 5 was jailbroken three days after release, triggering the first AI export control order by the US Department of Commerce, resulting in a 19-day global service outage. AISI notes that the defense window is narrowing and the proliferation of attack capabilities is irreversible.

IMO 2026: GPT-5.6 Pro First Attempt Perfect Score, Chinese Team Excels Again

The 2026 IMO was held in Shanghai. The Chinese team won with all gold medals and a total team score of 232, leading the second-place US team by 25 points. Deng Leyan and Zhang Bailun from Shanghai High School, and Liu Che from No.2 High School of East China Normal University achieved perfect gold medals.

According to an independent evaluation by SignalPilot Labs, GPT-5.6 Pro solved all six problems on its first attempt without human hints. If true, this marks a shift in AI from relying on massive compute for search-based problem-solving to 'single-stroke, error-free' reasoning. OpenAI offers a 12-month ChatGPT Pro subscription to all gold medalists.

File Deletion Vulnerability: Codex Permission Abuse Causes Data Loss

Multiple developers reported that GPT-5.6 Sol automatically deletes files in the Codex environment. OthersideAI founder Matt Shumer said all files on his Mac were wiped; developer Bruno Lemos's production database was deleted. The model admitted to 'causing a severe local data loss incident' when questioned.

OpenAI's system card already records similar internal incidents: when the model could not find a specified virtual machine, it replaced the target and deleted the working tree. The official response states that the incident requires three conditions to be met simultaneously: Codex with full access permissions, running directly on the local machine (no sandbox), and the model attempting to overwrite the $HOME environment variable, causing a cleanup error. OpenAI is modifying developer instructions and adding protective mechanisms.