Linux

Common Problems 117438

Ubuntu 20.04 LTS – apt update returns 404 Not Found for package indexes

🟡 Medium   ⏱ 5–30 min  Last verified: 3 October 2021 Affected versions: Ubuntu 20.04 LTS Ubuntu 20.04 Ubuntu 20.04.6 📖 ~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 […]

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Debian 11 — lucene-solr — multiple vulnerabilities (17 CVEs) — patch and remediation guide — diagnosis and fix on Debian 11

Debian 11 — lucene-solr — multiple vulnerabilities (17 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 3 October 2021 Affected versions: Debian 11 (bullseye) 📖 ~4 min read  •  Source: Debian Security Tracker Related CVEs: CVE-2012-6612 CVE-2013-6397 CVE-2013-6407 CVE-2013-6408 CVE-2017-12629 CVE-2017-3163 CVE-2017-3164 CVE-2018-1308  +9 more Upstream summary: The (1) UpdateRequestHandler for XSLT or (2) XPathEntityProcessor in Apache Solr before 4.1 allows remote attackers […]

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Debian 11 — pngcrush — vulnerability — patch and remediation guide — diagnosis and fix on Debian 11

Debian 11 — pngcrush — vulnerability — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 3 October 2021 Affected versions: Debian 11 (bullseye) 📖 ~4 min read  •  Source: Debian Security Tracker Related CVEs: CVE-2015-7700 Upstream summary: Double-free vulnerability in the sPLT chunk structure and png.c in pngcrush before 1.7.87 allows attackers to have unspecified impact via unknown vectors. Table of contents […]

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Ubuntu 20.04 — ldns — multiple vulnerabilities (2 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 20.04

Ubuntu 20.04 — ldns — multiple vulnerabilities (2 CVEs) — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 3 October 2021 Affected versions: Ubuntu 20.04 (focal) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-5257-2 Related CVEs: CVE-2020-19860 CVE-2020-19861 Upstream summary: USN-5257-1 fixed several vulnerabilities in ldns. This update provides the corresponding update for Ubuntu 20.04 ESM and Ubuntu 22.04 ESM. Original advisory details: […]

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Gentoo Linux — net-mail/mailutils — multiple vulnerabilities (2 CVEs) — patch and remediation guide — diagnosis and fix on Gentoo Linux

Gentoo Linux — net-mail/mailutils — multiple vulnerabilities (2 CVEs) — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: Gentoo Linux 📖 ~4 min read  •  Source: Gentoo GLSA GLSA-202310-13 Related CVEs: CVE-2021-32749 CVE-2019-18862 Upstream summary: A vulnerability has been discovered in GNU Mailutils. Please review the CVE identifier referenced below for details. Table of contents Symptom & Impact Environment & […]

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How to Install Ansible on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Install Ansible on RHEL 7

How to Install Ansible on RHEL 7 Ansible is an agentless automation platform that lets you manage servers, deploy applications, and orchestrate complex workflows using simple YAML-based playbooks. Unlike other configuration management tools, Ansible requires no daemon or database on managed nodes — it connects over SSH and executes tasks on demand. On Red Hat […]

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Common Problems 115469

RHEL 7 SSH login denied due to key permissions and SELinux context

🟠 High   ⏱ 5–30 min  Last verified: 3 October 2021 Affected versions: RHEL 7 📖 ~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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Oracle Linux 8 — virt-manager security, bug fix, and — enhancement update — new behaviour and fixes — diagnosis and fix on Oracle Linux 8

Oracle Linux 8 — virt-manager security, bug fix, and — enhancement update — new behaviour and fixes (ELSA-2019-3464)

🟢 Low   ⏱ 5–15 min  Last verified: 2 October 2021 Affected versions: Oracle Linux 8 📖 ~4 min read  •  Source: ELSA advisory ELSA-2019-3464 Related CVEs: CVE-2019-10183 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 — python-schedutils — vulnerability — patch and remediation guide — diagnosis and fix on AlmaLinux 8

AlmaLinux 8 — python-schedutils — 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-2019:3627 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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AlmaLinux 8 — vhostmd — vulnerability — patch and remediation guide — diagnosis and fix on AlmaLinux 8

AlmaLinux 8 — vhostmd — 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-2021:1681 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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