SwissBorg’s $41M Solana Heist Exposes API Vulnerability Crisis

SwissBorg, a Switzerland-based cryptocurrency wealth management platform, has confirmed a cyberattack that resulted in the theft of $41 million worth of Solana (SOL) tokens from its Earn program. The breach, which occurred on September 8, 2025, was attributed to a vulnerability in the application programming interface (API) of its staking partner, Kiln. According to the company, hackers exploited the API to manipulate requests and siphon off approximately 192,600 SOL tokens, valued at around $41.5 million at the time of the incident [4].

SwissBorg emphasized that the breach did not impact the broader platform, including its app or other Earn products, and that only a small segment of its user base—around 1% of users—was affected [1]. The company confirmed that the stolen funds were transferred to a Solana wallet labeled “SwissBorg Exploiter” on Solscan, a blockchain explorer [4]. In response, SwissBorg paused Solana staking transactions and activated an incident response plan in collaboration with Kiln and security partners to contain the breach and prevent further losses [3].

Despite the significant financial loss, the company reiterated that it remains financially stable and is capable of reimbursing affected users from its existing Solana treasury. SwissBorg CEO Cyrus Fazel described the incident as “a bad day, but not a fatal one” and expressed confidence in the firm’s ability to recover and continue operations [4]. The company is also working with exchanges, international enforcement agencies, and ethical hackers to trace and potentially recover the stolen assets. Some transactions have already been blocked by exchanges, signaling progress in the investigation [4].

The incident has reignited discussions about the risks of relying on third-party infrastructure in the cryptocurrency sector. SwissBorg's vulnerability highlights the broader challenges platforms face in securing their systems, particularly when dependent on external APIs and staking providers. The breach underscores the importance of rigorous security audits and the development of in-house solutions to minimize exposure to external threats [2].

Analysts have pointed to the increasing frequency of API-related attacks in the decentralized finance (DeFi) and staking ecosystems. This SwissBorg incident follows other high-profile hacks in September, including a $2.4 million exploit of the Nemo Protocol on the Sui blockchain [4]. The growing sophistication of these attacks has raised concerns among users and regulators alike, prompting calls for enhanced security measures and regulatory oversight.

SwissBorg has pledged to strengthen its security protocols and improve oversight of third-party risk, particularly in its staking operations. The company has directed users to its official X account for ongoing updates on the incident and recovery efforts [4]. Meanwhile, the broader crypto industry continues to grapple with the challenges of maintaining user trust in an environment where even well-established platforms remain vulnerable to cyber threats.

Source:

[1] SwissBorg hacked $41M in Solana after Kiln API ... (https://cointelegraph.com/news/swissborg-hacked-41m-sol-api-compromise)

[2] SwissBorg Grapples with Staking Breaches as 2025 Unfolds (https://www.onesafe.io/blog/swissborg-staking-breach-2025)

[3] SOL Incident & SwissBorg - Announcement (https://www.kiln.fi/post/sol-incident-swissborg---announcement)

[4] SwissBorg loses $41M in Solana following API-related hack (https://crypto.news/swissborg-crypto-loses-solana-api-related-hack-2025)