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CVE-2025-10035: Fortra GoAnywhere MFT deserialization to command injection, actively exploited

The short version: Fortra's GoAnywhere MFT has a deserialization flaw in its License Servlet (CVE-2025-10035): an attacker who can forge a valid license-response signature can deserialize an arbitrary object and drive it into command injection on the server. Fortra scores it a perfect 10.0, it's in CISA's KEV catalog, and it was exploited as a zero-day by a ransomware operator. Patch now. Steady hands — but move.

At a glance

FactDetail
Our severity takeHigh — in practice and on paper
CVSS v3.1 (NVD)9.8 — Critical · AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS (Fortra, CNA)10.0 — Critical · AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (Scope: Changed)
EPSS~99.6% · 99.95th percentile (2026-07-17)
In CISA KEV?Yes — added 2025-09-29; remediation was due 2025-10-20
Known exploited?Yes — exploited as a zero-day; attributed to ransomware activity (Storm-1175 / Medusa)
Vulnerability typeCWE-502 deserialization of untrusted data → command injection
Requires authenticated session?No — exploited without valid credentials via a forged license-response signature
AffectedGoAnywhere MFT prior to 7.6.3, and 7.7.0 through 7.8.3
Fixed inGoAnywhere MFT 7.8.4 (latest) and 7.6.3 (Sustain Release)

What you need to know

CVE-2025-10035 lives in the GoAnywhere License Servlet. An actor who can present a validly forged license-response signature can get the servlet to deserialize an attacker-controlled object — and that deserialization is the doorway to command injection on the underlying server.

  • How they find it — internet-wide scanning surfaces exposed GoAnywhere MFT interfaces.
  • How they use it — forge the license-response signature, feed a malicious serialized object to the servlet, and reach command execution; exploitation ran as a zero-day before the advisory.
  • What it leads to — code execution on a file-transfer platform holding sensitive data — the exact recipe that made GoAnywhere a repeat target for extortion crews.

How serious we see it

High — the 10.0 matches the field reports.

Network-reachable command injection on an internet-facing MFT platform, exploited as a zero-day and tied to ransomware, is top-of-queue. Fortra's 10.0 (Scope: Changed) reflects that a compromise reaches beyond the servlet's own boundary; NVD's 9.8 lands in the same Critical band. The bounded, reassuring part: specific versions are affected, fixes exist on both the latest and Sustain branches, and exposure is quick to determine. The catch is the pre-patch window — check for compromise, because a patched server isn't automatically a clean one.

Recommendations

Straight from Fortra's advisory (FI-2025-012) and CISA:

  1. Patch now. Upgrade to GoAnywhere MFT 7.8.4 (latest) or 7.6.3 (Sustain) or later.
  2. Get the admin console and license endpoint off the public internet. Restrict access to trusted networks — GoAnywhere's history argues strongly for this.
  3. Hunt for prior compromise. Given the zero-day window, review the server for unexpected processes, files, accounts, and outbound connections.
  4. If you find indicators, respond fully. Rebuild where warranted, rotate credentials and keys, and assess what data was reachable.
  5. Confirm your exposure first. Verify whether any GoAnywhere MFT is internet-facing and on an affected build.

How BreachRisk sees it

BreachRisk discovers internet-facing GoAnywhere MFT portals from little more than your domain, fingerprints the version, and flags exposure tied to KEV-listed, actively exploited flaws like this one — surfaced at the top of your results because it's in KEV. Where authorized, it goes beyond detection and safely performs a bounded, non-disruptive check against the affected endpoint to confirm it responds as a vulnerable instance would, rather than attempting the command injection itself.

That outside-in, continuous view is exactly what an actively exploited MFT flaw demands: the exposed platform is already mapped and ranked, so you go straight to patch-and-hunt.

References

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