Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck
CVE-2026-79787Alluxio through 2.9.5 S3 REST Proxy Authentication Bypass via Unverified Request Signature
Critical 9.8
In plain English
A critical-severity improper authentication in alluxio from Alluxio. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities).
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.5%top 60.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
Alluxio's S3 REST proxy fails to verify AWS Signature Version 4 signatures in its default configuration, allowing unauthenticated attackers to spoof user identity. Attackers can extract usernames from unsigned Authorization headers and impersonate any user, including service accounts, to read, write, and delete arbitrary data.
Affected products (as reported)
Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://github.com/Alluxio/alluxio product
- https://github.com/Alluxio/alluxio/issues/18755 issue-tracking
- https://github.com/Alluxio/alluxio/blob/v2.9.5/core/server/proxy/src/main/java/alluxio/proxy/s3/S3RestUtils.java technical-description
- VulnCheck Advisory: Alluxio through 2.9.5 S3 REST Proxy Authentication Bypass via Unverified Request Signature third-party-advisory