kernel: userfaultfd bypasses tmpfs file permissions
Published Dec 12, 2018
6.1
MEDIUMCVSS 3.0
EPSS 0.51%
Description
The userfaultfd implementation in the Linux kernel before 4.19.7 mishandles access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes), related to fs/userfaultfd.c and mm/userfaultfd.c.
Affected products
No data.
Configuration 1
- < 4.19.7
Configuration 2
- 3.11
- 4.0
- 7.0
- 7.0
- 7.4
- 7.6
- 7.4
- 7.5
- 7.6
- 7.4
- 7.6
- 7.0
Configuration 3
- 14.04
- 16.04
- 18.04
- 18.10
No data.
Red Hat Enterprise Linux 7
kernel-0:3.10.0-957.5.1.el7
Fixed · RHSA-2019:0163
Red Hat Enterprise Linux 7
kernel-alt-0:4.14.0-115.7.1.el7a
Fixed · RHSA-2019:0831
Red Hat Enterprise Linux 7.4 Extended Update Support
kernel-0:3.10.0-693.44.1.el7
Fixed · RHSA-2019:0324
Red Hat Enterprise Linux 7.5 Extended Update Support
kernel-0:3.10.0-862.27.1.el7
Fixed · RHSA-2019:0202
Red Hat Enterprise Linux 5
kernel
Not affected
Red Hat Enterprise Linux 6
kernel
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 7 | kernel-0:3.10.0-957.5.1.el7 | Fixed | RHSA-2019:0163 |
| Red Hat Enterprise Linux 7 | kernel-alt-0:4.14.0-115.7.1.el7a | Fixed | RHSA-2019:0831 |
| Red Hat Enterprise Linux 7.4 Extended Update Support | kernel-0:3.10.0-693.44.1.el7 | Fixed | RHSA-2019:0324 |
| Red Hat Enterprise Linux 7.5 Extended Update Support | kernel-0:3.10.0-862.27.1.el7 | Fixed | RHSA-2019:0202 |
| Red Hat Enterprise Linux 5 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 6 | kernel | 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.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
1 other source (Red Hat) ▾
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
AV:L/AC:L/Au:N/C:N/I:P/A:N
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 2, 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 2, 2026 | 0.51% (0.00510) | 41.38th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.51% (0.00510) | 39.21th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.09% (0.00089) | 23.29th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.04% (0.00044) | 11.89th | v3 (v2023.03.01) |
| Jul 2, 2024 | 0.04% (0.00044) | 10.25th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.04% (0.00044) | 8.24th | 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) |
| Feb 3, 2022 | 1.66% (0.01659) | 33.93th | v1 |
| Jan 6, 2022 | 1.66% (0.01659) | 33.23th | v1 |
| Sep 1, 2021 | 1.66% (0.01659) | 73.35th | v1 |
| Apr 14, 2021 | 1.66% (0.01659) | 0.00th | v1 |
References (18)
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=29ec90660d68bbdd69507c1c8b4e33aa299278b1 x_refsource_MISCPatchThird Party Advisory
- https://access.redhat.com/errata/RHBA-2019:0327 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0163 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0202 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0324 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0831 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2018-18397 Vendor Advisory
- https://bugs.chromium.org/p/project-zero/issues/detail?id=1700 x_refsource_MISCExploitIssue TrackingThird Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1641548 Issue Tracking
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.87 x_refsource_MISCPatchVendor Advisory
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.7 x_refsource_MISCPatchVendor Advisory
- https://github.com/torvalds/linux/commit/29ec90660d68bbdd69507c1c8b4e33aa299278b1 x_refsource_MISCPatchThird Party Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2018-18397
- https://usn.ubuntu.com/3901-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://usn.ubuntu.com/3901-2/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://usn.ubuntu.com/3903-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://usn.ubuntu.com/3903-2/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2018-18397
Change history (0)
No recorded changes yet.