Firo (FIRO), a privacy-focused cryptocurrency formerly known as Zcoin, advanced 33.3% over 24 hours on Friday, September 18, 2026, trading close to $1.06. The move followed a sequence of protocol events that included a mandatory hard fork addressing a Spark supply-integrity flaw and the deployment of a cross-chain wrapped version of the token on Ethereum, BNB Chain, and Ergo.
Price Snapshot
Data from CoinGecko recorded the asset at $1.06, with a 24-hour range of $0.7997 to $1.10 and a Bitcoin-denominated price of 0.00001353 BTC, up 28.0% against BTC.
Market capitalization and fully diluted valuation were both listed at $20.484 million. 24-hour trading volume stood at $181,714. Circulating supply was reported at 19.047 million FIRO against a maximum supply of 21.4 million, with the asset ranked #837 at the time of the snapshot.
Volume relative to market capitalization remains thin. Roughly $180,000 in daily turnover against a $20 million cap indicates that comparatively small orders can influence the price, a factor relevant to any interpretation of the daily gain.
Spark Vulnerability and the September 4 Hard Fork
Firo’s current privacy layer, Lelantus Spark, is a zero-knowledge protocol that conceals sender, recipient, and amount in on-chain transactions. On August 1, 2026, the project received a private disclosure from independent researcher Carter Annandale describing a flaw in the protocol.
In an advisory published on August 13, 2026, Firo confirmed the issue as a supply-integrity, or inflation, bug. Under specific conditions, an attacker could forge Spark coins during multi-input transactions. Single-input Spark spends were not affected. As a temporary mitigation, Firo released v0.14.17.2, which restricted Spark spends to one input per transaction. The project stated that existing wallets and keys remained valid, and separately warned that single-input-only spends could expose amount-correlation metadata.
A follow-up mandatory upgrade was distributed on August 27, 2026. The v0.14.18.0 release is scheduled for activation at block 1,371,000, estimated for approximately 10:00 Coordinated Universal Time (UTC) on September 4, 2026. After activation, multi-input Spark spending resumed under a new versioned spend format.
Firo said existing Spark coins, balances, addresses, and keys did not require migration, and that nodes that failed to upgrade would fall off the network. Signed binaries and source code were published through the project’s GitHub releases page.
Price action around the fork was uneven. Daily closes tracked by market aggregators showed FIRO near $0.70 on September 4 and $0.89 on September 5, followed by a pullback through mid-September and a fresh advance into September 17 and 18.
rsFIRO Deployment on Rosen Bridge
On September 15, 2026, Firo announced the launch of rsFIRO, a wrapped representation of FIRO issued through Rosen Bridge. Rosen Bridge is a decentralized cross-chain protocol that mints wrapped assets on connected networks, allowing native FIRO to be transferred out, traded on other chains, and later redeemed for native units.
The rollout added liquidity venues on three networks. On Ethereum, rsFIRO trades on Uniswap under contract 0x2744ea5ac9b11cb5e3cd63d3a88e858336aeddc2 with eight decimals. On BNB Chain, the token is available on PancakeSwap under contract 0x13cDb5F7f398F6AF2CC3B34EB04476af3488853f, also with eight decimals. On Ergo, the pool sits on Mew Finance.
Firo explicitly stated that rsFIRO is not a private token. Bridge transfers and decentralized exchange (DEX) trades on these networks are public and traceable. Spark privacy properties apply only after users move wrapped tokens back to native FIRO.
A recap posted through the project’s Telegram channel on September 17 said rsFIRO turnover had reached approximately 16% of native FIRO trading volume within days of launch. That figure originates from the project’s own communication channel rather than an independent data provider.
Mining Software and Access Updates
On September 18, 2026, Firo released Firominer 1.4.0, an open-source miner for the FiroPoW proof-of-work algorithm. The release restored Advanced Micro Devices (AMD) OpenCL support, updated NVIDIA Compute Unified Device Architecture (CUDA) to version 12.9, claimed hash rate performance within approximately 1% of closed-source alternatives, and carried no developer fee.
Separately, on September 8, 2026, Firo said FIRO had been listed on Nonlogs.io, an exchange that does not enforce Know Your Customer (KYC) checks, with three new trading pairs.
Regulatory Backdrop
Privacy coins continue to operate under tightening rules in several jurisdictions. Under the European Union (EU) Anti-Money Laundering (AML) framework, from July 10, 2027, crypto-asset service providers (CASPs) will be restricted from maintaining accounts that permit anonymisation through anonymity-enhancing coins.
Firo has previously appeared on Binance’s monitoring tag and lost some exchange listings during earlier regulatory cycles. Older research notes surfaced through CoinGecko’s sidebar, referencing wallet concentration and privacy-coin regulatory volatility, carried timestamps of roughly 305 to 308 days before the September 18 snapshot and did not correspond to new events on that date.
Background
Firo launched in 2016 under the name Zcoin and rebranded in October 2020. Its current privacy layer, Lelantus Spark, succeeded earlier iterations of the project’s confidential-transaction technology. Maximum supply is capped at 21.4 million tokens. The asset continues to trade well below its 2017 cycle peak, which several trackers list near $140. For a broader survey of confidential-transaction assets, readers can consult the Crypto Times primer on the top privacy coins to watch in 2026.
The September 18 rally rests on three verifiable developments: a completed Spark security hard fork, a new cross-chain wrapper covering Ethereum, BNB Chain, and Ergo, and a light order book that can amplify percentage moves. None of these on their own imply sustained demand, and daily turnover remains in the low six figures.
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