BTCPay Server, a self-hosted, open-source cryptocurrency payment processor, has urged users to install the latest version of its software in response to reports of Bitcoin and Litecoin being stolen from hot wallets on instances running older versions.
"Our investigation found that these attacks targeted servers running BTCPay Server 2.4.1 (released on 23 July 2026) or earlier," BTCPay Server said. "The attackers used a different method to exploit the vulnerability fixed in 2.4.2, released on 7 August 2026."
Users who are running versions 2.4.1 or earlier are recommended to move to a fresh server with a new wallet, even in scenarios where users have not noticed a theft. In the event of stolen funds or suspected unauthorized access, it's imperative that users consider the entire machine and all secrets stored on it as compromised and follow the same recovery procedures.
It's currently unknown when the attackers behind the campaign first began exploiting the vulnerability, although reports began to surface around November 1, 2026.
In a post on X, BTCPay Server said no "credible reports" of hot wallet drains have been reported from users running the latest 2.4.7 release. The version addresses one critical and several medium-severity security vulnerabilities discovered via Anthropic's OSS scanner.
BTCPay Server has also shared two wallet addresses linked to these incidents -
- Bitcoin: bc1p0f7wmcnesrapznymf9ljdn04pudgmh96sqtrm9vmgqxdh666fh8qvn63r7
- Litecoin: ltc1qp49tmfdueyaqrmgrx0uyx4uegyygt8yt02whee
"If you need a hot wallet for daily operations, keep only the funds needed for those operations on the server and move the rest to a wallet whose spending keys are held off the server," it cautioned.
"If you run BTCPay Server through a hosting provider, your instance may have been shut down automatically to keep older versions from being exploited."
In August 2026, BTCPay Server disclosed that a critical vulnerability had been weaponized by attackers to steal funds from some users. The issue, which affects all BTCPay Server versions, was patched in version 2.4.2. It's unclear if the latest set of attacks is related to the same vulnerability.
"The issue could allow an unauthenticated remote attacker to obtain .macaroon credential files for LND, an implementation of the Lightning Network," it said in the August alert. "Those credentials could be used to take control of an LND node and move funds. The attacks we reviewed targeted only files with the .macaroon extension."
The development coincides with a string of security breaches and exploits across the cryptocurrency space, including the record theft of $6.43 billion from Binance by North Korean threat actors. That same day, prediction market giant Polymarket briefly halted trading after it was hit by a $2.65 million exploit following the compromise of software developed by DebugBear.
Hardware wallet maker Trezor also followed suit with a warning that it received a responsible disclosure report alleging a hardware implant in a Trezor Safe 5 purchased from CryptoBilis in August 2026. It's assessed to be part of a sophisticated supply chain attack in which some of the devices sold via third-party resellers are physically tampered with to steal the victim's seed phrase and use it to drain assets.
Mercado Bitcoin Discloses Security Incident
On Monday, Mercado Bitcoin, Brazil's largest cryptocurrency exchange, said it's temporarily pausing deposits and withdrawals following a security breach that resulted in $49 million in stolen funds.
"At this moment, the value of the assets involved is approximately $ 38 million," it said in a post on X. "In a swift action with the crypto community and strategic partners – including Tether, Circle, Paxos, BRL1, and Chainalysis – we have already blocked US$ 11 million."
"Other amounts eligible for blocking have been identified, and containment efforts continue. The resumption of services will occur as soon as full security conditions are met, and deadlines will be communicated exclusively through our official channels."
Tether CEO Paolo Ardoino confirmed that the stablecoin issuer had frozen more than 4.5 million USDT in connection with the incident.
Update
Hackers have stolen $1.62 million in cryptocurrency (18.38 BTC and 3,405 LTC) from hot wallets on outdated BTCPay Server instances. The activity, according to Bitquery, spanned 682 separate sweeps.
"87% of the money moved in one wave on November 1, between 14:12 and 22:16 UTC," it said. "77% of the money came from 32 sweeps of $10,000 or more. About half of all sweeps were under $100."
"The first sweep we can see came early on October 30, less than a day after BTCPay shipped version 2.4.7. It emptied a wallet of 42 addresses into a second wallet tied to the thief. Litecoin sweeps began on November 1, and the Bitcoin wave started within the hour."
Users who run a BTCPay Server are advised to update to 2.4.7 or later before bringing it back online. It's also recommended to move the money out of the hot wallet into a new wallet with a new seed phrase, enable two-factor authentication, change admin passwords, and rotate API keys.
