Security Hardening

Common Problems 113908

RHEL 10 Subscription-Manager Reports System Not Registered

🔴 Critical   ⏱ 5–30 min  Last verified: 9 November 2025 Affected versions: RHEL 10 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution — Primary Fix Solution — Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & […]

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Debian 13 — opensmtpd — multiple vulnerabilities (9 CVEs) — patch and remediation guide — diagnosis and fix on Debian 13

Debian 13 — opensmtpd — multiple vulnerabilities (9 CVEs) — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 9 November 2025 Affected versions: Debian 13 (trixie) 📖 ~4 min read  •  Source: Debian Security Tracker Related CVEs: CVE-2013-2125 CVE-2015-7687 CVE-2020-35679 CVE-2020-35680 CVE-2020-7247 CVE-2020-8793 CVE-2020-8794 CVE-2023-29323  +1 more Upstream summary: OpenSMTPD before 5.3.2 does not properly handle SSL sessions, which allows remote attackers to cause a […]

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How to Set Up Nginx Load Balancing on SLES 16 — step-by-step SUSE Linux Enterprise 16 tutorial on Progressive Robot

How to Set Up Nginx Load Balancing on SLES 16

Introduction This tutorial covers How to Set Up Nginx Load Balancing on SLES 16 on SLES 16. SLES 16 (SUSE Linux Enterprise Server 16) is SUSE’s enterprise-grade Linux distribution. It uses the zypper package manager, AppArmor for mandatory access control, and systemctl for service management. Prerequisites Ensure your SLES 16 system is up to date: […]

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openSUSE Tumbleweed — k9s — multiple vulnerabilities (3 CVEs) — patch and remediation guide — diagnosis and fix on openSUSE Tumbleweed

openSUSE Tumbleweed — k9s — multiple vulnerabilities (3 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: openSUSE Tumbleweed 📖 ~4 min read  •  Source: SUSE advisory SUSE-SU-2025:20516-1 (see also SUSE bugzilla) Related CVEs: CVE-2025-53547 CVE-2024-26147 CVE-2023-25165 Upstream summary: Helm is a package manager for Charts for Kubernetes. Prior to 3.18.4, a specially crafted Chart.yaml file along with a […]

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Ubuntu 24.04 — jinja2 — multiple vulnerabilities (4 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 24.04

Ubuntu 24.04 — jinja2 — multiple vulnerabilities (4 CVEs) — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 9 November 2025 Affected versions: Ubuntu 24.04 (noble) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-7343-1 Related CVEs: CVE-2024-56201 CVE-2024-56326 CVE-2025-27516 CVE-2024-34064 Upstream summary: Rafal Krupinski discovered that Jinja2 did not properly restrict the execution of code in situations where templates are used maliciously. An […]

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How to Install Apache on SLES 16 — step-by-step SUSE Linux Enterprise 16 tutorial on Progressive Robot

How to Install Apache on SLES 16

Introduction This tutorial covers How to Install Apache on SLES 16 on SLES 16. SLES 16 (SUSE Linux Enterprise Server 16) is SUSE’s enterprise-grade Linux distribution. It uses the zypper package manager, AppArmor for mandatory access control, and systemctl for service management. Step 1 — Install Apache zypper install -y apache2 Step 2 — Enable […]

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openSUSE Leap 15.6 — orc — vulnerability — patch and remediation guide — diagnosis and fix on openSUSE Leap 15.6

openSUSE Leap 15.6 — orc — vulnerability — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: openSUSE Leap 15.6 📖 ~4 min read  •  Source: SUSE advisory RHSA-2024:6184 (see also SUSE bugzilla) Related CVEs: CVE-2024-40897 Upstream summary: Stack-based buffer overflow vulnerability exists in orcparse.c of ORC versions prior to 0.4.39. If a developer is tricked to process a […]

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SLES 16 — libxkbcommon0 — multiple vulnerabilities (7 CVEs) — patch and remediation guide — diagnosis and fix on SLES 16

SLES 16 — libxkbcommon0 — multiple vulnerabilities (7 CVEs) — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 9 November 2025 Affected versions: SLES 16 📖 ~4 min read  •  Source: SUSE advisory SUSE-CU-2021:232-1 (see also SUSE bugzilla) Related CVEs: CVE-2018-15854 CVE-2018-15855 CVE-2018-15856 CVE-2018-15857 CVE-2018-15858 CVE-2018-15862 CVE-2018-15864 Upstream summary: Unchecked NULL pointer usage in xkbcommon before 0.8.1 could be used by local attackers to crash […]

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How to Configure Nginx FastCGI Caching on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure Nginx FastCGI Caching on RHEL 9

Nginx FastCGI caching stores the output of PHP-FPM (or any FastCGI backend) responses as files on disk and serves them directly without hitting PHP for subsequent requests. For a WordPress site or PHP application serving the same page to many users, this can reduce PHP execution from 200ms to under 1ms and cut server load […]

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How to Configure Kernel Parameters with sysctl on SLES 16 — step-by-step SUSE Linux Enterprise 16 tutorial on Progressive Robot

How to Configure Kernel Parameters with sysctl on SLES 16

Introduction This tutorial covers How to Configure Kernel Parameters with sysctl on SLES 16 on SLES 16. SLES 16 (SUSE Linux Enterprise Server 16) is SUSE’s enterprise-grade Linux distribution. It uses the zypper package manager, AppArmor for mandatory access control, and systemctl for service management. Prerequisites Ensure your SLES 16 system is up to date: […]

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