virt: guest to host DoS by triggering an infinite loop in microcode via #AC exception
Published Nov 16, 2015
4.9
MEDIUMCVSS 2.0
EPSS 0.57%
Description
The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic or hang) by triggering many #AC (aka Alignment Check) exceptions, related to svm.c and vmx.c.
Affected products
No data.
Configuration 1
- ≤ 4.2.3
Configuration 2
- 4.3.0
- 4.3.1
- 4.3.2
- 4.3.3
- 4.3.4
- 4.4.0
- 4.4.1
- 4.4.2
- 4.4.3
- 4.4.4
- 4.5.0
- 4.5.1
- 4.5.2
- 4.5.3
- 4.5.5
- 4.6.0
- 4.6.1
- 4.6.2
- 4.6.3
- 4.6.4
- 4.6.5
- 4.6.6
Configuration 3
- ≥ 4.0.0 · ≤ 4.0.34
- ≥ 4.1.0 · ≤ 4.1.42
- ≥ 4.2.0 · ≤ 4.2.34
- ≥ 4.3.0 · ≤ 4.3.29
- ≥ 5.0.0 · ≤ 5.0.8
Configuration 4
- 7.0
- 8.0
Configuration 5
- 12.04
- 14.04
- 15.10
No data.
Red Hat Enterprise Linux 6
kernel-0:2.6.32-573.12.1.el6
Fixed · RHSA-2015:2636
Red Hat Enterprise Linux 6.2 Advanced Update Support
kernel-0:2.6.32-220.65.1.el6
Fixed · RHSA-2016:0046
Red Hat Enterprise Linux 6.4 Advanced Update Support
kernel-0:2.6.32-358.69.1.el6
Fixed · RHSA-2016:0004
Red Hat Enterprise Linux 6.5 Advanced Update Support
kernel-0:2.6.32-431.68.1.el6
Fixed · RHSA-2015:2645
Red Hat Enterprise Linux 6.6 Extended Update Support
kernel-0:2.6.32-504.40.1.el6
Fixed · RHSA-2016:0024
Red Hat Enterprise Linux 7
kernel-0:3.10.0-327.3.1.el7
Fixed · RHSA-2015:2552
Red Hat Enterprise Linux 7.1 Extended Update Support
kernel-0:3.10.0-229.24.2.ael7b
Fixed · RHSA-2015:2587
Red Hat Enterprise Linux 5
kernel
Not affected
Red Hat Enterprise Linux 5
kvm
Will not fix
Red Hat Enterprise Linux 5
xen
Will not fix
Red Hat Enterprise Linux 7
kernel-rt
Not affected
Red Hat Enterprise MRG 2
realtime-kernel
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel-0:2.6.32-573.12.1.el6 | Fixed | RHSA-2015:2636 |
| Red Hat Enterprise Linux 6.2 Advanced Update Support | kernel-0:2.6.32-220.65.1.el6 | Fixed | RHSA-2016:0046 |
| Red Hat Enterprise Linux 6.4 Advanced Update Support | kernel-0:2.6.32-358.69.1.el6 | Fixed | RHSA-2016:0004 |
| Red Hat Enterprise Linux 6.5 Advanced Update Support | kernel-0:2.6.32-431.68.1.el6 | Fixed | RHSA-2015:2645 |
| Red Hat Enterprise Linux 6.6 Extended Update Support | kernel-0:2.6.32-504.40.1.el6 | Fixed | RHSA-2016:0024 |
| Red Hat Enterprise Linux 7 | kernel-0:3.10.0-327.3.1.el7 | Fixed | RHSA-2015:2552 |
| Red Hat Enterprise Linux 7.1 Extended Update Support | kernel-0:3.10.0-229.24.2.ael7b | Fixed | RHSA-2015:2587 |
| Red Hat Enterprise Linux 5 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 5 | kvm | Will not fix | n/a |
| Red Hat Enterprise Linux 5 | xen | Will not fix | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise MRG 2 | realtime-kernel | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue affects the version of the kvm and xen packages as shipped with Red Hat Enterprise Linux 5. This issue does not affect the versions of the kernel package as shipped with Red Hat Enterprise Linux 5 and Red Hat Enterprise MRG 2. This issue affects the version of Linux kernel as shipped with Red Hat Enterprise Linux 6 and 7. Future kernel updates for the respective releases may address this issue. Red Hat Enterprise Linux 5 is now in Production Phase 3 of the support and maintenance life cycle. Thus it is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
AV:L/AC:L/Au:N/C:N/I:N/A:C
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (15 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.57% (0.00566) | 44.96th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.57% (0.00571) | 42.52th | v5 (v2026.06.15) |
| Mar 30, 2025 | 0.26% (0.00261) | 46.53th | v4 (v2025.03.14) |
| Mar 29, 2025 | 2.63% (0.02631) | 76.12th | v4 (v2025.03.14) |
| Mar 17, 2025 | 0.26% (0.00261) | 47.43th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.07% (0.00074) | 33.88th | v3 (v2023.03.01) |
| Jun 13, 2024 | 0.07% (0.00074) | 31.79th | v3 (v2023.03.01) |
| Feb 16, 2024 | 0.07% (0.00074) | 29.76th | v3 (v2023.03.01) |
| Jan 14, 2024 | 0.07% (0.00068) | 28.30th | v3 (v2023.03.01) |
| Sep 8, 2023 | 0.06% (0.00055) | 20.89th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.07% (0.00068) | 27.85th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.55% (0.01547) | 74.98th | v2 (v2022.01.01) |
| Feb 23, 2023 | 1.55% (0.01547) | 74.94th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.55% (0.01547) | 72.92th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.55% (0.01547) | 51.82th | v2 (v2022.01.01) |
References (41)
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- https://nvd.nist.gov/vuln/detail/CVE-2015-5307
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Change history (0)
No recorded changes yet.