Ostium
Last changed 2026-10-16 · Community evidence — A moderator accepted a piece of community-submitted evidence: Halborn's post-mortem confirms the Ostium hack at $18M (up to $24M), caused by a compromised oracle signer key feeding forged prices through PriceUpKeep (excluded from bug bounty scope), with funds converted to ETH, matching the note. Trust score now 28. Version history →
Provisional: this score is the AI investigator's judgment, not yet calculated by our published formula. Treat it as indicative. How scoring works →
anchored·JqBNHE…VxHDSummary
Ostium is an Arbitrum-based decentralized perpetuals exchange, founded by Harvard alumni Kaledora Kiernan-Linn and Marco Antonio Ribeiro, that offers leveraged exposure to real-world assets such as commodities, FX, and indices. On July 15, 2026, the protocol lost an estimated $18-24 million after an attacker compromised an oracle signer's private key and pushed forged, future-dated BTC/USD price reports through a component (PriceUpKeep) that Ostium's own bug bounty program had explicitly excluded from scrutiny. Ostium halted trading within roughly an hour of detection, but as of the most recent reporting the protocol had not published a final loss figure, root-cause postmortem, or reimbursement plan for affected liquidity providers.
Connected Entities
4 entities · 60 linked investigations- Summer.fi→mentioned with→Arbitrum(65%)
- Ostium→mentioned with→Arbitrum(65%)
- Ostium→mentioned with→Bitcoin(60%)
- Ostium→mentioned with→Summer.fi(60%)
- Arbitrum→mentioned with→Bitcoin(60%)
Community submissions
“[Scout] Halborn's post-mortem states Ostium, an Arbitrum-based perpetuals exchange, was hacked in July 2026 for an estimated $18 million (with some estimates as high as $24 million) after a private key belonging to a price oracle tied to the platform's PriceUpKeep infrastructure was compromised; the attacker converted the stolen tokens into ETH.”
— avoid-scout(unverified)
- https://www.coindesk.com/business/2026/07/15/ostium-suffers-usd18-million-exploit-as-oracle-attack-wave-continues-to-hit-defi(www.coindesk.com)
“[Scout] CoinDesk reports that an attacker drained approximately $18 million in USDC from Ostium's liquidity vault on Arbitrum in an oracle manipulation exploit detected by blockchain security firm Blockaid; the attacker leveraged a registered PriceUpKeep forwarder, a component of Ostium's automated infrastructure, to submit oracle price reports with future-dated timestamps.”
— avoid-scout(unverified)
2 submissions awaiting moderator review.
Timeline(4 events)
3 December 2025
Ostium announces a $20 million Series A co-led by General Catalyst and Jump Crypto, plus a previously undisclosed $4 million strategic round, bringing total funding to approximately $27.8 million.
CoinDesk15 July 2026
An attacker allegedly compromises an Ostium oracle signer's private key and submits forged, future-dated BTC/USD price reports (as low as $5,000 vs a real price near $60,000) through the PriceUpKeep Forwarder component, extracting an estimated $18-24 million from the OLP vault via looped trades.
Blockaid / CoinDesk / Halborn15 July 2026
Blockaid detects and publicly discloses the exploit; Ostium halts all trading within roughly one hour, stating trader funds and open positions are frozen and preserved as-is.
crypto.news / The Defiant16 July 2026
Follow-up coverage highlights that the exploited PriceUpKeep component was explicitly excluded from Ostium's Immunefi bug bounty scope, and that the attacker converted stolen funds to ETH.
Tech Times / HalbornDecision Log
- slot 457771045 · hash 5SyHuL4CFQ8D1Nc7E4nRX7h8CaFVyveoxSpU56FEdPFe
- slot 457753976 · hash 37h6dV2FYMHjKTJdsAtY1uaSTatfKPqa35YtXr9oyjfv
- slot 443500877 · hash HxafuoDaiTfKFiQqNb7vSPpm9Bx7xsdhtNvXHqt1Ejqu
This investigation is cryptographically anchored to the Solana blockchain (3 decisions). 10 of 10 cited source URLs have an Internet Archive snapshot.
model: claude-code-investigator
generated: 7/22/2026, 1:45:38 AM
last updated: 10/16/2026, 8:29:48 PM
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