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Ubuntu CVE-2018-18653

HIGH
Improper Verification of Cryptographic Signature (CWE-347)
2018-10-26 cve@mitre.org
7.8
CVSS 3.0 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Signature verification
Impact

CVSS score of 7.8 (HIGH). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

Successful exploitation could compromise the high-severity affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAI

The Linux kernel, as used in Ubuntu 18.10 and when booted with UEFI Secure Boot enabled, allows privileged local users to bypass intended Secure Boot restrictions and execute untrusted code by. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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Technical ContextAI · show details

This vulnerability is classified under CWE-347. The Linux kernel, as used in Ubuntu 18.10 and when booted with UEFI Secure Boot enabled, allows privileged local users to bypass intended Secure Boot restrictions and execute untrusted code by loading arbitrary kernel modules. This occurs because a modified kernel/module.c, in conjunction with certain configuration options, leads to mishandling of the result of signature verification. Affected products include: Canonical Ubuntu Linux.

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Severity by source

NVD PRIMARY 7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionNVD

The Linux kernel, as used in Ubuntu 18.10 and when booted with UEFI Secure Boot enabled, allows privileged local users to bypass intended Secure Boot restrictions and execute untrusted code by loading arbitrary kernel modules. This occurs because a modified kernel/module.c, in conjunction with certain configuration options, leads to mishandling of the result of signature verification.

Threat Intelligence Overview

EPSS Score
0.3%
Top 77% exploitable
Exploit
POC
Public exploit code exists
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Small
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

59
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +39
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Affected Products (CPE)NVD

cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*
CVE-2013-3900 MEDIUM
5.5 Dec 11

Why is Microsoft republishing a CVE from 2013? We are republishing CVE-2013-3900 in the Security Update Guide to update

CVE-2026-48558 CRITICAL POC
9.5 Jun 12

Authentication bypass in SimpleHelp 5.5.15 and prior (plus 6.0 pre-release builds) allows remote unauthenticated attacke

CVE-2026-5430 CRITICAL POC
10.0 Aug 06

Authentication bypass in WSO2 API Manager and related components (Universal Gateway, Traffic Manager, API Control Plane,

CVE-2025-59718 CRITICAL
9.8 Dec 09

Authentication bypass in Fortinet FortiOS, FortiProxy, and FortiSwitchManager allows unauthenticated remote attackers to

CVE-2025-25291 CRITICAL POC
9.3 Mar 12

ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. Rated critical severity (CVS

CVE-2026-47304 CRITICAL POC
9.8 Jul 14

Security feature bypass in Microsoft .NET (shipped via Visual Studio 2022 17.12/17.14 and Visual Studio 2026 18.7) lets

CVE-2025-25292 CRITICAL POC
9.3 Mar 12

ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. Rated critical severity (CVS

CVE-2022-25898 CRITICAL POC
9.8 Jul 01

The package jsrsasign before 10.5.25 are vulnerable to Improper Verification of Cryptographic Signature when JWS or JWT

CVE-2026-107722 CRITICAL POC
9.8 Oct 08

Authentication and authorization bypass in fast-jwt 6.2.0 through 6.2.4 (npm, NearForm) lets a remote, unauthenticated a

CVE-2024-42004 CRITICAL POC
9.8 Dec 18

A library injection vulnerability exists in Microsoft Teams (work or school) 24046.2813.2770.1094 for macOS. Rated criti

CVE-2024-41145 CRITICAL POC
9.8 Dec 18

A library injection vulnerability exists in the WebView.app helper app of Microsoft Teams (work or school) 24046.2813.27

CVE-2024-41138 CRITICAL POC
9.8 Dec 18

A library injection vulnerability exists in the com.microsoft.teams2.modulehost.app helper app of Microsoft Teams (work

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