[This CNA information record relates to multiple CVEs; the
text explains which aspects/vulnerabilities correspond to which CVE.]

libfsimage contains parsing code for several filesystems, most of them based on
grub-legacy code. libfsimage is used by pygrub to inspect guest disks.

Pygrub runs as the same user as the toolstack (root in a priviledged domain).

At least one issue has been reported to the Xen Security Team that allows an
attacker to trigger a stack buffer overflow in libfsimage. After further
analisys the Xen Security Team is no longer confident in the suitability of
libfsimage when run against guest controlled input with super user priviledges.

In order to not affect current deployments that rely on pygrub patches are
provided in the resolution section of the advisory that allow running pygrub in
deprivileged mode.

CVE-2023-4949 refers to the original issue in the upstream grub
project ("An attacker with local access to a system (either through a
disk or external drive) can present a modified XFS partition to
grub-legacy in such a way to exploit a memory corruption in grub’s XFS
file system implementation.") CVE-2023-34325 refers specifically to
the vulnerabilities in Xen's copy of libfsimage, which is decended
from a very old version of grub.
Advisories
Source ID Title
EUVD EUVD EUVD-2023-38406 [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] libfsimage contains parsing code for several filesystems, most of them based on grub-legacy code. libfsimage is used by pygrub to inspect guest disks. Pygrub runs as the same user as the toolstack (root in a priviledged domain). At least one issue has been reported to the Xen Security Team that allows an attacker to trigger a stack buffer overflow in libfsimage. After further analisys the Xen Security Team is no longer confident in the suitability of libfsimage when run against guest controlled input with super user priviledges. In order to not affect current deployments that rely on pygrub patches are provided in the resolution section of the advisory that allow running pygrub in deprivileged mode. CVE-2023-4949 refers to the original issue in the upstream grub project ("An attacker with local access to a system (either through a disk or external drive) can present a modified XFS partition to grub-legacy in such a way to exploit a memory corruption in grub’s XFS file system implementation.") CVE-2023-34325 refers specifically to the vulnerabilities in Xen's copy of libfsimage, which is decended from a very old version of grub.
Fixes

Solution

No solution given by the vendor.


Workaround

Ensuring that guests do not use the pygrub bootloader will avoid this vulnerability. For cases where the PV guest is known to be 64bit, and uses grub2 as a bootloader, pvgrub is a suitable alternative pygrub. Running only HVM guests will avoid the vulnerability.

History

Wed, 18 Jun 2025 16:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


cve-icon MITRE

Status: PUBLISHED

Assigner: XEN

Published:

Updated: 2025-06-18T15:47:10.373Z

Reserved: 2023-06-01T10:44:17.065Z

Link: CVE-2023-34325

cve-icon Vulnrichment

Updated: 2024-08-02T16:10:06.291Z

cve-icon NVD

Status : Modified

Published: 2024-01-05T17:15:08.590

Modified: 2025-06-18T16:15:20.987

Link: CVE-2023-34325

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.