Troubleshooting

Arch Linux — go — multiple vulnerabilities (20 CVEs) — patch and remediation guide

• April 13, 2021
• Linux
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🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: Arch Linux (rolling release) 📖 ~4 min read  •  Source: Arch ASA ASA-202011-16 Related CVEs: CVE-2020-28367 CVE-2020-28366 CVE-2020-28362 CVE-2018-16875 CVE-2018-16874 CVE-2018-16873 CVE-2018-6574 CVE-2017-15041  +12 more Upstream summary: Type: multiple issues. Status: Fixed. Affected: 2:1.15.4-1. Fixed in: 2:1.15.5-1. Group: AVG-1278. Table of contents […]

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SLES 15 — apache2-mod_auth_mellon — vulnerability — patch and remediation guide

• April 13, 2021
• Linux
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🟡 Medium   ⏱ 10–30 min  Last verified: 13 April 2021 Affected versions: SLES 15 📖 ~4 min read  •  Source: SUSE advisory SUSE-SU-2021:2912-1 (see also SUSE bugzilla) Related CVEs: CVE-2021-3639 Upstream summary: A flaw was found in mod_auth_mellon where it does not sanitize logout URLs properly. This issue could be used by an attacker […]

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Oracle Linux 8 — gcc — security and stability fixes — required update (ELSA-2020-1864)

• April 12, 2021
• Linux
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🟡 Medium   ⏱ 10–30 min  Last verified: 12 April 2021 Affected versions: Oracle Linux 8 📖 ~4 min read  •  Source: ELSA advisory ELSA-2020-1864 Related CVEs: CVE-2019-15847 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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Ubuntu 16.04 LTS cloud-init stalls first boot

• April 12, 2021
• Linux
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🟡 Medium   ⏱ 5–30 min  Last verified: 12 April 2021 📖 ~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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Windows Server 2012 R2 — AAD Connect sync conflict on user attribute causes export error — Fix & Prevention

• April 12, 2021
• Tutorials
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🟠 High   ⏱ 5–30 min  Last verified: 12 April 2021 Affected versions: Windows Server 2012 R2 📖 ~2 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 […]

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AlmaLinux 8 — rshim — vulnerability — patch and remediation guide

• April 12, 2021
• Linux
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🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: AlmaLinux 8 📖 ~4 min read  •  Source: AlmaLinux ALSA ALBA-2021:4228 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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How to Configure TeamCity Build Agent on Oracle Linux 8

• April 12, 2021
• Oracle Linux
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Introduction How to Configure TeamCity Build Agent on Oracle Linux 8 on Oracle Linux 8 provides administrators with a robust, enterprise-ready workflow that integrates cleanly with systemd, SELinux, firewalld, and the modern AppStream module system. In this tutorial we will walk through every step required, from package installation to verification, so that the resulting configuration […]

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IBM AIX 7.1 — CVE-2021-38931 — information disclosure — patch and remediation guide

• April 12, 2021
• Tutorials
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🟡 Medium   ⏱ 15–45 min  Last verified: 12 April 2021 Affected versions: IBM AIX 7.1 📖 ~4 min read  •  Source: NVD CVE-2021-38931, IBM Support Bulletin CVE: CVE-2021-38931 NVD summary: IBM Db2 for Linux, UNIX and Windows (includes DB2 Connect Server) 11.1, and 11.5 is vulnerable to an information disclosure as a result of […]

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Gentoo Linux — games-board/gnuchess — vulnerability — patch and remediation guide

• April 12, 2021
• Linux
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🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: Gentoo Linux 📖 ~4 min read  •  Source: Gentoo GLSA GLSA-202107-28 Related CVEs: CVE-2021-30184 Upstream summary: The cmd_pgnload() and cmd_pgnreplay() functions in cmd.cc in GNU Chess to not sufficiently validate PGN file input, potentially resulting in a buffer overflow. Table of contents […]

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How to Set Up Port Knocking on Debian 9

• April 12, 2021
• Linux
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Introduction Deploying set up port knocking on debian 9 on a Debian 9 Stretch machine is straightforward thanks to Debian’s policy-compliant packaging. Unlike rpm-based distributions, Debian stores configuration helpers in /etc/default/, uses update-rc.d for older init scripts, and provides dpkg-reconfigure for interactive package configuration. This tutorial stays on the systemd path throughout. Prerequisites Ensure Debian […]

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