SEPTEMBER 14, 2026
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Case File

CVE-2026-88018

CRITICAL · CVSS 9.8 EPSS 0.49% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-10 · Last synced 2026-09-14

CyberRota Analysis

AI-Generated

Rclone versions prior to 1.75.1 are vulnerable when using the `serve s3` command with the `--auth-proxy` option without an `--auth-key`, allowing unauthenticated attackers to exploit the authPairMiddleware and gain unauthorized access to backend services. This critical vulnerability can lead to unauthorized data access and manipulation, posing significant risks to cloud storage security. Organizations utilizing rclone for file synchronization should prioritize upgrading to version 1.75.1 or later to mitigate this risk.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

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CVE
CVE-2026-88018
Severity
CRITICAL
CVSS
9.8
EPSS
0.49%

Original NVD Description

rclone is a command-line program to sync files and directories to and from different cloud storage providers. Prior to 1.75.1, rclone serve s3 configured with --auth-proxy but without --auth-key allows authPairMiddleware to register any client-chosen accessKeyID with an empty ws.s3Secret. gofakes3 then verifies the request’s SigV4 signature against that same empty secret, while Server.auth passes the access key identifier as both the user and authentication value to the proxy without an independent per-identity secret. An unauthenticated network attacker can therefore choose an arbitrary access key, sign with an empty secret, and reach whatever backend the auth-proxy script resolves for that identity. This issue is fixed in version 1.75.1.