CVE-2018-18021: canonical ubuntu_linux Improper Input Validation
Vulnerability summary
CVE-2018-18021 is a high (CVSS 7.1) Improper Input Validation vulnerability in canonical ubuntu_linux. EPSS estimates a 0.59% chance of exploitation in the next 30 days, higher than 48.4% of scored vulnerabilities.
Not severe (CVSS 7.1, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 7 · Related 4Timeline
- 07-10-2018PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
Description
arch/arm64/kvm/guest.c in KVM in the Linux kernel before 4.18.12 on the arm64 platform mishandles the KVM_SET_ON_REG ioctl. This is exploitable by attackers who can create virtual machines. An attacker can arbitrarily redirect the hypervisor flow of control (with full register control). An attacker can also cause a denial of service (hypervisor panic) via an illegal exception return. This occurs because of insufficient restrictions on userspace access to the core register file, and because PSTATE.M validation does not prevent unintended execution modes.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.1HighCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.1HighCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
EPSS trend
Probability
0.59%
Chance of exploitation in the next 30 days
Percentile
48%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.59% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu18 products
- linuxAll versions (No fix recorded) | < 4.4.0-139.165 | < 4.15.0-47.50
- linux-aws-hwe< 4.15.0-1035.37~16.04.1
- linux-azure-6.11All versions (No fix recorded)
- linux-azure-fdeAll versions (No fix recorded)
- linux-fips< 4.4.0-1008.10
Debian2 products
- linux< 4.18.10-2
- debian_linuxEOL9.0
Canonical1 product
- ubuntu_linuxEOL14.04 | 16.04
Linux1 product
- linux_kernel< 4.18.12
4 vendors · 22 products
References
22 links- github.com/torvalds/linux/commit/2a3f93459d689d990b3ecfbe782fec89b97d3279X Refsource MISCPatchREPORT
- www.openwall.com/lists/oss-security/2018/10/02/2X Refsource MISCMailing ListPatchThird Party AdvisoryREPORT
- github.com/torvalds/linux/commit/d26c25a9d19b5976b319af528886f89cf455692dX Refsource MISCPatchREPORT
