Process exhaustion via unbounded CONNECT response headers
Published Aug 5, 2026 · Updated Aug 5, 2026
Resource exhaustion in Rclone rclone before 1.75.0 allows remote attackers to crash the process via oversized HTTP CONNECT headers. HTTPConnectDial in lib/proxy/http.go passes an unrestricted buffered connection to http.ReadResponse, which accepts proxy response headers without a size ceiling. Exploitation requires rclone to use a malicious or compromised FTP or SFTP HTTP CONNECT proxy, or a plaintext proxy hop controlled on path, and memory exhaustion can interrupt unrelated remotes and mounts.
Summary
What happened
Resource exhaustion in Rclone rclone before 1.75.0 allows remote attackers to crash the process via oversized HTTP CONNECT headers. HTTPConnectDial in lib/proxy/http.go passes an unrestricted buffered connection to http.ReadResponse, which accepts proxy response headers without a size ceiling. Exploitation requires rclone to use a malicious or compromised FTP or SFTP HTTP CONNECT proxy, or a plaintext proxy hop controlled on path, and memory exhaustion can interrupt unrelated remotes and mounts.
The record
- CVE
- CVE-2026-71310
- Published
- Aug 5, 2026
- Updated
- Aug 5, 2026
- Vendor
- Rclone
- Product
- rclone
- Classifications
- CWE-770, CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 5, 2026CVE publishedPublication date reported by the CVE source.
- Aug 5, 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
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
- GHSA-xhf4-832v-7xcr HTTP CONNECT header proof of conceptproof of concept · 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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