Guest-to-host escape via unchecked CE record bounds
Published Jul 28, 2026 · Updated Jul 28, 2026
Improper input validation in Xen 3.2 and later allows guest OS users using pygrub to escalate to domain-construction-tool privileges. The libfsimage ISO9660 Rock Ridge CE handler trusts attacker-controlled continuation-area size and offset fields when walking an on-disk image, permitting buffer overruns. A crafted guest filesystem is processed only when pygrub boots the guest; without deprivileged pygrub, the resulting execution context normally controls the host.
Summary
What happened
Improper input validation in Xen 3.2 and later allows guest OS users using pygrub to escalate to domain-construction-tool privileges. The libfsimage ISO9660 Rock Ridge CE handler trusts attacker-controlled continuation-area size and offset fields when walking an on-disk image, permitting buffer overruns. A crafted guest filesystem is processed only when pygrub boots the guest; without deprivileged pygrub, the resulting execution context normally controls the host.
The record
- CVE
- CVE-2026-62425
- Published
- Jul 28, 2026
- Updated
- Jul 28, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-20, T1068
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Jul 28, 2026CVE publishedPublication date reported by the CVE source.
- Jul 28, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
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