Cross-guest memory disclosure via premature cache cleaning
Published Feb 17, 2021 · Updated Aug 3, 2024
Information disclosure in Xen 4.9 and later on Arm allows guest OS users to read memory data previously held by another guest. The Arm page-allocation path cleans the cache before checking whether a page was scrubbed, so scrub writes are not guaranteed to reach memory before reassignment. Exploitation requires control of a guest on an Arm host and exposes residual cross-guest memory without changing data or interrupting service.
Summary
What happened
Information disclosure in Xen 4.9 and later on Arm allows guest OS users to read memory data previously held by another guest. The Arm page-allocation path cleans the cache before checking whether a page was scrubbed, so scrub writes are not guaranteed to reach memory before reassignment. Exploitation requires control of a guest on an Arm host and exposes residual cross-guest memory without changing data or interrupting service.
The record
- CVE
- CVE-2021-26933
- Published
- Feb 17, 2021
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- T1005
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 17, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo