Rclone 1.75.0 S3 Multipart Declared-Length Memory Exhaustion (CVE-2026-88045)

high Nessus Plugin ID 346830

Synopsis

An application installed on the remote host is affected by a denial of service vulnerability.

Description

The version of Rclone installed on the remote host is 1.75.0. It is, therefore, affected by a denial of service vulnerability:

- In streamed multipart mode, rclone serve s3 passes the request's declared part length to multipart.NewRW().Reserve(contentLength) before reading any part data, which immediately obtains enough 1 MiB pool pages for the entire declared length. A network client can therefore cause the server to reserve memory proportional to an unverified Content-Length or X-Amz-Decoded-Content-Length header without transmitting the corresponding body, and
--multipart-streaming-buffer-limit does not cap the allocation for the current expected part.
A sufficiently large declared length, or concurrent requests, can exhaust process or host memory or permanently block request goroutines, resulting in loss of S3 service availability.
(CVE-2026-88045)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to Rclone version 1.75.1 or later.

Plugin Details

Severity: High

ID: 346830

File Name: rclone_CVE-2026-88045.nasl

Version: 1.2

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 9/17/2026

Updated: 9/18/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.65

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-88045

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:rclone:rclone

Required KB Items: installed_sw/rclone

Exploit Ease: No known exploits are available

Patch Publication Date: 9/4/2026

Vulnerability Publication Date: 9/10/2026

Reference Information

CVE: CVE-2026-88045

Detections

Analytics