Guest disk disclosure via permissive qemu-img umask
Published Aug 10, 2026 · Updated Aug 10, 2026
Information disclosure in libvirt on Red Hat Enterprise Linux 6 through 10 allows local users to read guest disk contents. On non-NETFS storage paths, virStorageBackendCreateExecCommand runs qemu-img with umask 0, creating mode-0644 images before a later chmod restricts them. Exploitation requires local access during a volume clone or conversion, and the race exposes the full source guest disk without enabling modification.
Summary
What happened
Information disclosure in libvirt on Red Hat Enterprise Linux 6 through 10 allows local users to read guest disk contents. On non-NETFS storage paths, virStorageBackendCreateExecCommand runs qemu-img with umask 0, creating mode-0644 images before a later chmod restricts them. Exploitation requires local access during a volume clone or conversion, and the race exposes the full source guest disk without enabling modification.
The record
- CVE
- CVE-2026-63623
- Published
- Aug 10, 2026
- Updated
- Aug 10, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 6
- Classifications
- CWE-732, T1005
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 10, 2026CVE publishedPublication date reported by the CVE source.
- Aug 10, 2026Record 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?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
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
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