Buffer Overflow Affecting xen package, versions [4.17,]


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-UNMANAGED-XEN-5563882
  • published19 May 2023
  • disclosed19 May 2023
  • creditUnknown

Introduced: 19 May 2023

CVE-2022-42336  (opens in a new tab)
CWE-120  (opens in a new tab)

How to fix?

A fix was pushed into the master branch but not yet published.

Overview

Affected versions of this package are vulnerable to Buffer Overflow such that it is possible for a guest to under or overflow the thread counter, because each write to VIRT_SPEC_CTRL.SSBD by the guest gets propagated to the helper that does the per-core active accounting. Underflowing the counter causes the value to get saturated, and thus attempts for guests running on the same core to set SSBD won't have an effect because the hypervisor assumes it's already active.

Note:

Only x86 AMD systems are vulnerable. The vulnerability can be leveraged by and affects only HVM guests.

Workaround

Running PV guests only will prevent the vulnerability.

Setting spec-ctrl=ssbd on the hypervisor command line will force SSBD to be unconditionally active.

CVSS Scores

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