Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2018-18955

46
FAUCET Score

CVE-2018-18955 is a local privilege escalation vulnerability in Linux kernel versions 4.15.x through 4.19.1, affecting Canonical and Linux distributions. It arises from improper handling of nested user namespaces with more than five UID or GID ranges, allowing a user with CAP_SYS_ADMIN in an affected namespace to bypass access controls and read sensitive files like /etc/shadow. With a CVSS score of 7.0 (HIGH), this vulnerability has a low attack complexity and requires local access, but can lead to full compromise of confidentiality, integrity, and availability. While not currently on the KEV catalog, multiple public exploits exist, including Metasploit modules and several ExploitDB entries, indicating readily available attack vectors. Despite the availability of exploit code, there is minimal community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 4.15, < 4.19.2CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
18.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
18.10CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.0HIGH

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.0
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
7.61%
Probability of exploitation in next 30 days
EPSS Percentile
93.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
Metasploit: Linux Nested User Namespace idmap Limit Local Privilege Escalation · Nov 15, 2018
ExploitDB: EDB-47167 · Jan 4, 2019
This CVE's current EPSS score of 0.0761 is in the 99th percentile among its peer group of 1,525 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.4 InfoSec Media, 0.1 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2018-18955Important

kernel: Privilege escalation in map_write() in kernel/user_namespace.c

Nov 15, 2018

References

git.kernel.org / cgit/linux/kernel/git/torvalds/linux.git/commit
PatchVendor Advisory
bugs.chromium.org / p/project-zero/issues/detail
PatchThird Party Advisory
cdn.kernel.org / pub/linux/kernel/v4.x/ChangeLog-4.18.19
PatchVendor Advisory
cdn.kernel.org / pub/linux/kernel/v4.x/ChangeLog-4.19.2
PatchVendor Advisory
github.com / torvalds/linux/commit/d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd
PatchVendor Advisory
security.netapp.com / advisory/ntap-20190416-0003
support.f5.com / csp/article/K39103040
usn.ubuntu.com / 3832-1
Third Party Advisory
usn.ubuntu.com / 3833-1
Third Party Advisory
usn.ubuntu.com / 3835-1
Third Party Advisory
usn.ubuntu.com / 3836-1
Third Party Advisory
usn.ubuntu.com / 3836-2
Third Party Advisory
exploit-db.com / exploits/45886
ExploitPatchThird Party AdvisoryVDB Entry
exploit-db.com / exploits/45915
ExploitThird Party AdvisoryVDB Entry
securityfocus.com / bid/105941
Third Party AdvisoryVDB Entry