CVE-2026-88044 is a critical-severity (CVSS 9.1) CWE-863 vulnerability. O3 Security confirms whether CVE-2026-88044 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
rclone is a command-line program to sync files and directories to and from different cloud storage providers. From 1.70.0 until 1.75.1, the serve/start RC interface accepts per-server…
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-88044.
Description
rclone is a command-line program to sync files and directories to and from different cloud storage providers. From 1.70.0 until 1.75.1, the serve/start RC interface accepts per-server proxyOpt.AuthProxy settings, and the FTP and S3 constructors in cmd/serve/ftp/ftp.go and cmd/serve/s3/server.go incorrectly check the process-global proxy.Opt.AuthProxy value instead. When the global value is empty, the request-local authentication proxy is ignored: FTP falls back to the fixed filesystem with username anonymous and any password, while S3 with AuthKey serves the fixed RC fs rather than the backend selected by the proxy. The dedicated command-line servers that configure the global option are not affected. This issue is fixed in version 1.75.1.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-88044 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-88044 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-88044. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-88044 in your dependencies?
O3 detects CVE-2026-88044 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.