CVE-2018-18397

Exp

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.

Published: 2018-12-12 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-18397 is rated Exploit Available (51.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.51%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2018-18397

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2018-18397

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.07% 0.51% +0.44%
2 2025-11-21 0.05% 0.07% +0.02%
3 2025-11-18 — 0.05% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-18397

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.0 MEDIUM
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.8 3.6 [email protected]
2.1 2.0 LOW
AV:L/AC:L/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 3.9 2.9 [email protected]

Weakness enumeration for CVE-2018-18397

OS Trackers for CVE-2018-18397

vendor priority summary link
debian not yet assigned CVE-2018-18397 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-18397
redhat medium — https://access.redhat.com/security/cve/CVE-2018-18397
suse medium CVE-2018-18397 severity moderate: SUSE including 136 source package names (bpftool-3.10.0-957.5.1.el7, cluster-md-kmp-azure-4.12.14-5.19.1, …), 488 product×package rows across 100 product lines (HPE Helion OpenStack 8, SLES for SAP Applications 11 SP2, … (100 product lines)): Known Not Affected 307, Fixed 181. https://www.suse.com/security/cve/CVE-2018-18397/
ubuntu medium CVE-2018-18397 medium priority: Ubuntu including 27 source packages (linux, linux-aws, …), 135 status rows across 5 suites (bionic, cosmic, trusty, upstream, xenial): DNE 69, released 53, not-affected 11, ignored 2. https://ubuntu.com/security/CVE-2018-18397

Affected software / configurations for CVE-2018-18397

Vendor Product Version Raw CPE
linux linux_kernel < 4.19.7 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
redhat openshift_container_platform 3.11 cpe:2.3:a:redhat:openshift_container_platform:3.11:*:*:*:*:*:*:*
redhat virtualization_host 4.0 cpe:2.3:a:redhat:virtualization_host:4.0:*:*:*:*:*:*:*
redhat enterprise_linux_desktop 7.0 cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
redhat enterprise_linux_server 7.0 cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.4 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.6 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.4 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.4:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.5 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.5:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.6 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.4 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.4:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.6 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:*
redhat enterprise_linux_workstation 7.0 cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:*
canonical ubuntu_linux 14.04 cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 18.10 cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*

References for CVE-2018-18397

URL Tags
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=29ec90660d68bbdd69507c1c8b4e33aa299278b1 Patch Third Party Advisory
https://access.redhat.com/errata/RHBA-2019:0327 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:0163 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:0202 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:0324 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:0831 Third Party Advisory
https://bugs.chromium.org/p/project-zero/issues/detail?id=1700 Exploit Issue Tracking Third Party Advisory
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.87 Patch Vendor Advisory
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.7 Patch Vendor Advisory
https://github.com/torvalds/linux/commit/29ec90660d68bbdd69507c1c8b4e33aa299278b1 Patch Third Party Advisory
https://usn.ubuntu.com/3901-1/ Third Party Advisory
https://usn.ubuntu.com/3901-2/ Third Party Advisory
https://usn.ubuntu.com/3903-1/ Third Party Advisory
https://usn.ubuntu.com/3903-2/ Third Party Advisory
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