Authorization Flaw in github.com/rclone/rclone (CVE-2026-88044)
Summary
Vulnerability in github.com/rclone/rclone (CVE-2026-88044). Confidential information can be exposed externally. Exploitable via proxyOpt. Mitigation: upgrade to 1.75.1 or later.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-88044 has been found in github.com/rclone/rclone.
Attackers can target a specific entry point like proxyOpt over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 9.1/10.
What to do: upgrade github.com/rclone/rclone to 1.75.1 or later.
If unsure, ask your IT team or search "github.com/rclone/rclone CVE-2026-88044" on the vendor's site.
CVE-2026-88044 (github.com/rclone/rclone) — CWE-863 / CVSS v3 9.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: proxyOpt / proxy.Opt.AuthProxy / proxyOpt.AuthProxy / anonymous
Patched: 1.75.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Incorrect authorization (CWE-863) exists in github.com/rclone/rclone. Attackers reach the vulnerable code path via proxyOpt without authentication.
Check the vendor advisory for the affected versions of github.com/rclone/rclone. Attack surface: proxyOpt / proxy.Opt.AuthProxy / proxyOpt.AuthProxy / anonymous.
Severity: Critical (CVSS 9.1/10). Confidential information can be exposed externally.
Update to 1.75.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/rclone/rclone' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/rclone/rclone' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/rclone/rcloneを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/rclone/rclone to 1.75.1ステージング環境で 1.75.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-88044 rclone
References
- web github.com
- web github.com
- web github.com
- web nvd.nist.gov
- web github.com