Hack history / 2026 / Hack or exploit
Notional V2
Hack or exploit on Sep 3, 2026 · Arithmetic Error
SOURCES AGREE ON DATE AND LOSS · 3 SOURCES
Lost
$1.7M
dollars at the time
Returned
none listed
as the sources state it
Rank
#749
among thefts by dollars lost
What happened
An attacker exploited an unchecked uint128 cast in Notional V1’s collateral valuation logic. By minting two fCash positions against the same payer with notionals of 1 and 2^128-1, the attacker engineered a debt balance of exactly 2^128. When the free-collateral check converted the debt to ETH, uint128(balance.abs()) truncated 2^128 to zero, making the insolvent payer appear to have no debt. The attacker then settled the fabricated fCash claims and withdrew approximately $1.73M in USDC and DAI from the Escrow
Details
- Date
- Sep 3, 2026
- Kind
- Hack or exploit
- Method
- Arithmetic Error
- How in
- Smart contract bug
- Target
- DeFi protocol
- Chains
- Ethereum
Reported by
Related incidents
Nesa 2026 · Hack or exploit · $50M
Truebit 2026 · Hack or exploit · $26.4M
KiiChain 2026 · Hack or exploit · $9.7M
TMX TRIBE 2026 · Hack or exploit · $1.4M
Little Boy Plus 2026 · Hack or exploit · $367K
Truebit 2026 · Hack or exploit · $26.4M
KiiChain 2026 · Hack or exploit · $9.7M
TMX TRIBE 2026 · Hack or exploit · $1.4M
Little Boy Plus 2026 · Hack or exploit · $367K
Cite this page
SwanBluechip, "Notional V2 hack, Sep 3, 2026: $1.7M lost", Crypto hack history, https://swan-hack-tracker.pages.dev/history/i/htecd9ab372e/ (data as of 2026-10-31).