S3 service denial via declared-length memory reservation
Published Sep 10, 2026 · Updated Sep 10, 2026
Resource exhaustion in Rclone rclone 1.75.0 allows remote attackers to interrupt S3 service via streamed multipart requests. The serve S3 multipart handler passes an unverified declared length to Reserve before reading body bytes, causing immediate allocation of 1 MiB pool pages. Anonymous deployments require no credentials; authenticated deployments require an accepted S3 key, and retained or concurrent requests can exhaust host memory or block handlers permanently.
Summary
What happened
Resource exhaustion in Rclone rclone 1.75.0 allows remote attackers to interrupt S3 service via streamed multipart requests. The serve S3 multipart handler passes an unverified declared length to Reserve before reading body bytes, causing immediate allocation of 1 MiB pool pages. Anonymous deployments require no credentials; authenticated deployments require an accepted S3 key, and retained or concurrent requests can exhaust host memory or block handlers permanently.
The record
- CVE
- CVE-2026-88045
- Published
- Sep 10, 2026
- Updated
- Sep 10, 2026
- Vendor
- Rclone
- Product
- rclone
- Classifications
- CWE-789, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 10, 2026CVE publishedPublication date reported by the CVE source.
- Sep 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 1.75.0, < 1.75.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Loopback HTTP declared-length allocation demonstrationfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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