kernel: xen: race condition in event-channel removal during the event-handling loop (XSA-331)
Published Oct 22, 2020
4.7
MEDIUMCVSS 3.1
EPSS 0.27%
Description
An issue was discovered in the Linux kernel through 5.9.1, as used with Xen through 4.14.x. drivers/xen/events/events_base.c allows event-channel removal during the event-handling loop (a race condition). This can cause a use-after-free or NULL pointer dereference, as demonstrated by a dom0 crash via events for an in-reconfiguration paravirtualized device, aka CID-073d0552ead5.
Affected products
No data.
Configuration 1
- ≤ 5.9.1
Configuration 2
- 31
- 32
- 33
Configuration 3
- 9.0
No data.
Red Hat Enterprise Linux 5
kernel
Out of support scope
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel
Not affected
Red Hat Enterprise Linux 7
kernel-alt
Not affected
Red Hat Enterprise Linux 7
kernel-rt
Not affected
Red Hat Enterprise Linux 8
kernel
Not affected
Red Hat Enterprise Linux 8
kernel-rt
Not affected
Red Hat Enterprise MRG 2
kernel-rt
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 5 | kernel | Out of support scope | n/a |
| Red Hat Enterprise Linux 6 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel-alt | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise MRG 2 | kernel-rt | Not affected | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
No CVSS v3.0 score for this CVE.
AV:L/AC:M/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 4, 2026.
Score over time
2021-2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (14 key points)
Flat stretches are collapsed. Showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 4, 2026 | 0.27% (0.00269) | 17.28th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.27% (0.00265) | 17.66th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.08% (0.00077) | 20.69th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.04% (0.00045) | 16.02th | v3 (v2023.03.01) |
| Jun 10, 2024 | 0.04% (0.00045) | 14.07th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.04% (0.00045) | 12.06th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.28% (0.01282) | 68.34th | v2 (v2022.01.01) |
| Feb 22, 2023 | 1.28% (0.01282) | 68.05th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.28% (0.01282) | 65.91th | v2 (v2022.01.01) |
| Feb 4, 2022 | 4.80% (0.04804) | 74.65th | v2 (v2022.01.01) |
| Feb 3, 2022 | 9.45% (0.09448) | 86.95th | v1 |
| Jan 6, 2022 | 9.45% (0.09448) | 86.79th | v1 |
| Sep 1, 2021 | 2.27% (0.02273) | 77.89th | v1 |
| Apr 14, 2021 | 2.27% (0.02273) | 0.00th | v1 |
References (14)
- http://www.openwall.com/lists/oss-security/2021/01/19/3 mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2020-27675 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1891114 Issue Tracking
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=073d0552ead5bfc7a3a9c01de590e924f11b5dd2 x_refsource_MISCPatchVendor Advisory
- https://github.com/torvalds/linux/commit/073d0552ead5bfc7a3a9c01de590e924f11b5dd2 x_refsource_MISCPatchThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/12/msg00027.html mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3ZG6TZLD23QO3PV2AN2HB625ZX47ALTT/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6USZ4APZSBQDHGJLJMHW5JBN4QZV6SKZ/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GNF2R7FUT4IOJ2RIRGQ7X5R4F4FVVLSR/ vendor-advisoryx_refsource_FEDORA
- https://nvd.nist.gov/vuln/detail/CVE-2020-27675
- https://security.gentoo.org/glsa/202011-06 vendor-advisoryx_refsource_GENTOOThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2020-27675
- https://xenbits.xen.org/xsa/advisory-331.html x_refsource_MISCPatchVendor Advisory
Change history (0)
No recorded changes yet.