On october 21 2026, two PHP bugs took Wikipedia and the Internet Archive offline. Security people are calling it Black October. On october 27, frontrun posted 10 early AI security startups it had already flagged. A fuller version, with the screenshots, is in our post on X. Follower counts below are from that post.
the 10 startups
| company | what it does | followers | flagged |
|---|---|---|---|
| Pensar (@runpensar) | continuous adversarial testing. seed led by Basis Set Ventures. founders @proulxkerem, @kylebhiro. pensar.dev | 217 | sep 4 |
| OpenHack (@openhack) | always-on AI security engineer. YC F26, backed by @solofounders. founder @ananayarora. openhack.com | 923 | sep 26 |
| Parameter (@parameter_ai) | continuous testing for web apps, APIs and infrastructure. YC W26, formerly Hex Security. founders @zer0day, @hzzzaifa, @menace_codes. parameter.ai | 354 | oct 13 |
| Hinoki Security (@hinokisecurity) | Hinoki Offensive One, an open-access offensive model for Claude Code, Codex and Cursor. hinoki.security | 133 | oct 2 |
| AdverserialAI (@adverserialAI) | two cybersecurity models, served so the data stays sealed. founder @lordx64. adverserial.ai | 253 | sep 2 |
| Exponential Security Labs (@expsecai) | multi-agent security environments for RL training. founder @nmndsingh. expsec.ai | 432 | jun 2 |
| Armorer Labs (@Armorer_Labs) | agent security for regulated industries, including armorer guard at runtime. YC F26, no priced round announced. founders @begimher, @cristian_le0. armorerlabs.com | 17 | oct 13 |
| InferTrail (@InferTrail) | spots AI abuse in usage logs without reading prompts or responses. no funding announced. founder @polydaic. infertrail.com | 49 | sep 7 |
| Vigilbase (@vigilbase) | a cybersecurity operating system over the tools a team already pays for. no outside funding announced. founder @ilyesm. vigilbase.com | 17 | sep 2 |
| Mirage Security (@miragesecurity) | simulates AI social engineering against a team before an attacker does. founder @rosslazer. miragesecurity.ai | 34 | oct 19 |
The post says this category got hot in the previous couple of weeks, and that these 10 are a slice of the security startups flagged on frontrun. Armorer Labs is also on YC F26 under 25 followers. OpenHack is F26 too, next to the full F26 list. More companies in the neighborhood: AI startups, devtools, and AI labs under 500 followers.
Frontrun finds founders and startups first. The AI deal flow agent for venture investors.
follow from the front: frontrun.vc
open source deal flow
companies and founders surfaced on frontrun. curated, every week.