Fortra on Thursday revealed the results of its investigation into CVE-2025-10035, a critical security flaw in GoAnywhere Managed File Transfer (MFT) that's assessed to have come under active exploitation since at least September 11, 2025.
The company said it began its investigation on September 11 following a "potential vulnerability" reported by a customer, uncovering "potentially suspicious activity" related to the flaw.
That same day, Fortra said it contacted on-premises customers who were identified as having their GoAnywhere admin console accessible to the public internet and that it notified law enforcement authorities about the incident.
A hotfix for versions 7.6.x, 7.7.x, and 7.8.x of the software was made available the next day, with full releases incorporating the patch – versions 7.6.3 and 7.8.4 – made available on September 15. Three days later, a CVE for the vulnerability was formally published, it added.
"The scope of the risk of this vulnerability is limited to customers with an admin console exposed to the public internet," Fortra said. "Other web-based components of the GoAnywhere architecture are not affected by this vulnerability."
However, it conceded that there are a "limited number of reports" of unauthorized activity related to CVE-2025-10035. As additional mitigations, the company is recommending that users restrict admin console access over the internet, as well as enable monitoring and keep software up-to-date.
CVE-2025-10035 concerns a case of deserialization vulnerability in the License Servlet that could result in command injection without authentication. In a report earlier this week, Microsoft revealed that a threat it tracks as Storm-1175 has been exploiting the flaw since September 11 to deploy Medusa ransomware.
That said, there is still no clarity on how the threat actors managed to obtain the private keys needed to exploit this vulnerability.
"The fact that Fortra has now opted to confirm (in their words) 'unauthorized activity related to CVE-2025-10035' demonstrates yet again that the vulnerability was not theoretical and that the attacker has somehow circumvented, or satisfied, the cryptographic requirements needed to exploit this vulnerability," watchTowr CEO and founder Benjamin Harris said.
