Credential exposure via incomplete S3 redirect sanitization
Published Aug 25, 2026 · Updated Aug 25, 2026
Credential exposure in rclone before 1.75.0 allows man-in-the-middle attackers to capture IBM IAM tokens or SSE-C keys via S3 redirects. The s3CheckRedirect callback removes only X-Amz-Security-Token, leaving Authorization bearer tokens and SSE-C key headers attached when scheme or origin changes. Exploitation requires a trusted endpoint to issue an unsafe redirect and an on-path observer; captured tokens permit operations within IAM scope, while keys expose corresponding protected objects.
Summary
What happened
Credential exposure in rclone before 1.75.0 allows man-in-the-middle attackers to capture IBM IAM tokens or SSE-C keys via S3 redirects. The s3CheckRedirect callback removes only X-Amz-Security-Token, leaving Authorization bearer tokens and SSE-C key headers attached when scheme or origin changes. Exploitation requires a trusted endpoint to issue an unsafe redirect and an on-path observer; captured tokens permit operations within IAM scope, while keys expose corresponding protected objects.
The record
- CVE
- CVE-2026-79780
- Published
- Aug 25, 2026
- Updated
- Aug 25, 2026
- Vendor
- Rclone
- Product
- rclone
- Classifications
- CWE-201, CWE-522, CWE-200, CWE-319, T1040
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 25, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 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=0 <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
- Upstream S3 redirect callback proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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