kernel: Use-after-free in userfaultfd_event_wait_completion function in userfaultfd.c
Published Jan 14, 2018
8.1
HIGHCVSS 3.1
EPSS 4.08%
Description
A use-after-free flaw was found in fs/userfaultfd.c in the Linux kernel before 4.13.6. The issue is related to the handling of fork failure when dealing with event messages. Failure to fork correctly can lead to a situation where a fork event will be removed from an already freed list of events with userfaultfd_ctx_put().
Affected products
- Vendor n/a Product Linux Kernel before 4.13.6 Defaultn/a
- Version Linux Kernel before 4.13.6StatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| n/a | Linux Kernel before 4.13.6 | n/a |
|
- ≥ 4.11 · < 4.13.6
No data.
Red Hat Enterprise Linux 7
kernel-0:3.10.0-862.el7
Fixed · RHSA-2018:1062
Red Hat Enterprise Linux 7
kernel-rt-0:3.10.0-862.rt56.804.el7
Fixed · RHSA-2018:0676
Red Hat Enterprise Linux 5
kernel
Not affected
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel-alt
Not affected
Red Hat Enterprise Linux 8
kernel
Not affected
Red Hat Enterprise MRG 2
realtime-kernel
Affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 7 | kernel-0:3.10.0-862.el7 | Fixed | RHSA-2018:1062 |
| Red Hat Enterprise Linux 7 | kernel-rt-0:3.10.0-862.rt56.804.el7 | Fixed | RHSA-2018:0676 |
| 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-alt | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel | Not affected | n/a |
| Red Hat Enterprise MRG 2 | realtime-kernel | Affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5 and 6. This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 7, realtime, MRG-2 prior to version kernel-3.10.0-781. The kernel-alt package already as shipped contains this fix.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
AV:N/AC:M/Au:N/C:C/I:C/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
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v5
Table of values (16 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 4.08% (0.04075) | 90.38th | v5 (v2026.06.15) |
| Jun 15, 2026 | 4.10% (0.04102) | 89.41th | v5 (v2026.06.15) |
| Jul 20, 2024 | 2.53% (0.02534) | 90.32th | v3 (v2023.03.01) |
| Sep 3, 2023 | 2.53% (0.02534) | 88.81th | v3 (v2023.03.01) |
| Jul 17, 2023 | 1.80% (0.01803) | 86.50th | v3 (v2023.03.01) |
| Jun 7, 2023 | 1.68% (0.01680) | 85.87th | v3 (v2023.03.01) |
| May 8, 2023 | 1.44% (0.01435) | 84.55th | v3 (v2023.03.01) |
| Mar 7, 2023 | 2.01% (0.02013) | 87.08th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.18% (0.01183) | 61.76th | v2 (v2022.01.01) |
| Oct 19, 2022 | 1.18% (0.01183) | 60.79th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.18% (0.01183) | 58.77th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.18% (0.01183) | 35.15th | v2 (v2022.01.01) |
| Feb 3, 2022 | 1.86% (0.01865) | 48.06th | v1 |
| Jan 6, 2022 | 1.86% (0.01865) | 47.54th | v1 |
| Sep 1, 2021 | 1.86% (0.01865) | 76.13th | v1 |
| Apr 14, 2021 | 1.86% (0.01865) | 0.00th | v1 |
References (10)
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=384632e67e0829deb8015ee6ad916b180049d252 x_refsource_MISCVendor Advisory
- http://www.securityfocus.com/bid/102516 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- https://access.redhat.com/errata/RHSA-2018:0676 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2018:1062 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2017-15126 x_refsource_MISCThird Party AdvisoryVendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1523481 x_refsource_MISCIssue TrackingThird Party Advisory
- https://github.com/torvalds/linux/commit/384632e67e0829deb8015ee6ad916b180049d252 x_refsource_MISCThird Party Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2017-15126
- https://www.cve.org/CVERecord?id=CVE-2017-15126
- https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.6 x_refsource_MISCVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=384632e67e0829deb8015ee6ad916b180049d252 | x_refsource_MISCVendor Advisory | |
| http://www.securityfocus.com/bid/102516 | vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry | |
| https://access.redhat.com/errata/RHSA-2018:0676 | vendor-advisoryx_refsource_REDHATThird Party Advisory | |
| https://access.redhat.com/errata/RHSA-2018:1062 | vendor-advisoryx_refsource_REDHATThird Party Advisory | |
| https://access.redhat.com/security/cve/CVE-2017-15126 | x_refsource_MISCThird Party AdvisoryVendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1523481 | x_refsource_MISCIssue TrackingThird Party Advisory | |
| https://github.com/torvalds/linux/commit/384632e67e0829deb8015ee6ad916b180049d252 | x_refsource_MISCThird Party Advisory | |
| https://nvd.nist.gov/vuln/detail/CVE-2017-15126 | ||
| https://www.cve.org/CVERecord?id=CVE-2017-15126 | ||
| https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.6 | x_refsource_MISCVendor Advisory |
Change history (0)
No recorded changes yet.