Unauthenticated user impersonation via unverified request signatures
Published Aug 25, 2026 · Updated Aug 25, 2026
Authentication bypass in Alluxio 2.9.5 and earlier allows remote attackers to impersonate any user through the S3 REST proxy. S3RestUtils.getUser() parses the Credential field of an AWS4 Authorization header without verifying its signature when REST authentication is disabled. The default configuration selects this path, granting the claimed user's ability to read, write, overwrite, and delete Alluxio data.
Summary
What happened
Authentication bypass in Alluxio 2.9.5 and earlier allows remote attackers to impersonate any user through the S3 REST proxy. S3RestUtils.getUser() parses the Credential field of an AWS4 Authorization header without verifying its signature when REST authentication is disabled. The default configuration selects this path, granting the claimed user's ability to read, write, overwrite, and delete Alluxio data.
The record
- CVE
- CVE-2026-79787
- Published
- Aug 25, 2026
- Updated
- Aug 25, 2026
- Vendor
- Alluxio
- Product
- Alluxio
- Classifications
- CWE-287, T1190
- Attack vector
- network
- 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 <=2.9.5
What conditions does exploitation require?
What is affected?
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.
Public exploit references
- Alluxio S3 REST proxy fabricated-signature proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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