Linux

Ubuntu 16.04 — opensmtpd — multiple vulnerabilities (3 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 16.04

Ubuntu 16.04 — opensmtpd — multiple vulnerabilities (3 CVEs) — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: Ubuntu 16.04 (xenial) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-4875-1 Related CVEs: CVE-2020-7247 CVE-2020-8793 CVE-2020-8794 Upstream summary: It was discovered that OpenSMTPD incorrectly verified the sender's or receiver's e-mail addresses under certain conditions. An attacker could possibly use this […]

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Ubuntu 18.04 — pcre3 — multiple vulnerabilities (2 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 18.04

Ubuntu 18.04 — pcre3 — multiple vulnerabilities (2 CVEs) — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 25 May 2026 Affected versions: Ubuntu 18.04 (bionic) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-5425-1 Related CVEs: CVE-2019-20838 CVE-2020-14155 Upstream summary: Yunho Kim discovered that PCRE incorrectly handled memory when handling certain regular expressions. An attacker could possibly use this issue to cause applications […]

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Einrichten einer Firewall mit UFW unter Ubuntu 20.04 — step-by-step Linux tutorial on Progressive Robot

Einrichten einer Firewall mit UFW unter Ubuntu 20.04

UFW (oder Uncomplicated Firewall) ist eine vereinfachte Firewall-Verwaltungsschnittstelle, die die Komplexität von Paketfilterungstechnologie auf niedriger Ebene wie iptables und nftables versteckt. Wenn Sie mit dem Sichern Ihres Netzwerks beginnen möchten und Sie nicht…

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SLES 12 — python-httplib2 — multiple vulnerabilities (2 CVEs) — patch and remediation guide — diagnosis and fix on SLES 12

SLES 12 — python-httplib2 — multiple vulnerabilities (2 CVEs) — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: SLES 12 📖 ~4 min read  •  Source: SUSE advisory SUSE-CU-2021:236-1 (see also SUSE bugzilla) Related CVEs: CVE-2020-11078 CVE-2021-21240 Upstream summary: In httplib2 before version 0.18.0, an attacker controlling unescaped part of uri for `httplib2.Http.request()` could change request headers and body, send […]

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How To Secure Nginx with Let's Encrypt on Ubuntu 16.04 — step-by-step Linux tutorial on Progressive Robot

How To Secure Nginx with Let’s Encrypt on Ubuntu 16.04

In this tutorial, we will show you how to use Let’s Encrypt to obtain a free SSL certificate and use it with Nginx on Ubuntu 16.04. We will also show you how to automatically renew your SSL certificate. If you’re running a different web server, simply follow your web server’s documentation to learn how to use the certificate with your setup.

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How to Configure CMake Build System on Debian 9 — step-by-step Debian 9 tutorial on Progressive Robot

How to Configure CMake Build System on Debian 9

Introduction How to Configure CMake Build System on Debian 9 is a fundamental operation for any administrator maintaining a Debian 9 Stretch server. Debian 9 Stretch ships with the Linux 6.12 kernel, updated toolchains, and a fully refreshed package archive — meaning version numbers, configuration file paths, and some dependency chains differ from Debian 9. […]

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Oracle Linux 8 — xmlrpc-c — security and stability fixes — required update — diagnosis and fix on Oracle Linux 8

Oracle Linux 8 — xmlrpc-c — security and stability fixes — required update (ELSA-2024-4259)

🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: Oracle Linux 8 📖 ~4 min read  •  Source: ELSA advisory ELSA-2024-4259 Related CVEs: CVE-2023-52425 Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance […]

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AlmaLinux 8 — ibus-typing-booster — vulnerability — patch and remediation guide — diagnosis and fix on AlmaLinux 8

AlmaLinux 8 — ibus-typing-booster — vulnerability — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: AlmaLinux 8 📖 ~4 min read  •  Source: AlmaLinux ALSA ALBA-2021:1942 Upstream summary: For detailed information on changes in this release, see the AlmaLinux Release Notes linked from the References section. Table of contents Symptom & Impact Environment & Reproduction Root Cause […]

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Common Problems 114395

RHEL 9: dnf Metadata Download Timeout and Mirror Errors

🟡 Medium   ⏱ 5–30 min  Last verified: 19 May 2026 📖 ~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 & Cross-Refs References & Further […]

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AlmaLinux 8 — python-pyghmi — vulnerability — patch and remediation guide — diagnosis and fix on AlmaLinux 8

AlmaLinux 8 — python-pyghmi — vulnerability — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: AlmaLinux 8 📖 ~4 min read  •  Source: AlmaLinux ALSA ALEA-2021:4331 Upstream summary: For detailed information on changes in this release, see the AlmaLinux Release Notes linked from the References section. Table of contents Symptom & Impact Environment & Reproduction Root Cause […]

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