Linux

Common Problems 118402

Ubuntu 16.04 LTS – apt update fails with Release file not valid yet – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026 Affected versions: Ubuntu 16.04 LTS 📖 ~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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Common Problems 113900

RHEL 10 – dnf fails with SSL certificate verification error against repo mirror – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026 Affected versions: RHEL 10.0 RHEL 10.1 📖 ~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 […]

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Common Problems 117906

Ubuntu 18.04 LTS – apt update fails with Release file not valid yet – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026 Affected versions: Ubuntu 18.04 LTS 📖 ~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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Common Problems 119966

Debian 12 Repository GPG Key Expired During apt update

🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026 Affected versions: Debian 12 📖 ~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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SLES 15 — perl-Cpanel-JSON-XS — vulnerability — patch and remediation guide — diagnosis and fix on SLES 15

SLES 15 — perl-Cpanel-JSON-XS — vulnerability — patch and remediation guide

🔴 Critical   ⏱ 15–90 min  Last verified: 25 May 2026 Affected versions: SLES 15 📖 ~4 min read  •  Source: SUSE advisory SUSE-SU-2025:03193-1 (see also SUSE bugzilla) Related CVEs: CVE-2025-40929 Upstream summary: Cpanel::JSON::XS before version 4.40 for Perl has an integer buffer overflow causing a segfault when parsing crafted JSON, enabling denial-of-service attacks or […]

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CentOS Stream 9 — python-pyasn1 — vulnerability — patch and remediation guide — diagnosis and fix on CentOS Stream 9

CentOS Stream 9 — python-pyasn1 — vulnerability — patch and remediation guide

🟠 High   ⏱ 15–60 min  Last verified: 25 May 2026 Affected versions: CentOS Stream 9 📖 ~4 min read  •  Source: AlmaLinux/RHEL advisory ALSA-2026:3359 Related CVEs: CVE-2026-23490 Upstream summary: Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces […]

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Debian 9 — ffmpeg — multiple vulnerabilities (8 CVEs) — patch and remediation guide — diagnosis and fix on Debian 9

Debian 9 — ffmpeg — multiple vulnerabilities (8 CVEs) — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: Debian 9 (stretch) 📖 ~4 min read  •  Source: Debian Security Tracker Related CVEs: CVE-2017-9608 CVE-2017-14054 CVE-2017-15186 CVE-2017-17081 CVE-2018-6392 CVE-2018-14395 CVE-2018-15822 CVE-2019-12730 Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix […]

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Common Problems 114902

RHEL 8 RPM Database Locked or Corrupted During Package Operations

🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026 Affected versions: 8.4 8.5 8.6 8.7 8.8 8.9 8.10 📖 ~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 […]

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Debian 10 — tomcat9 — multiple vulnerabilities (6 CVEs) — patch and remediation guide — diagnosis and fix on Debian 10

Debian 10 — tomcat9 — multiple vulnerabilities (6 CVEs) — patch and remediation guide

🟡 Medium   ⏱ 10–30 min  Last verified: 25 May 2026 Affected versions: Debian 10 (buster) 📖 ~4 min read  •  Source: Debian Security Tracker Related CVEs: CVE-2019-10072 CVE-2020-9484 CVE-2020-13943 CVE-2021-25122 CVE-2021-30640 CVE-2021-41079 Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – […]

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Common Problems 115908

Ubuntu 26.04 LTS – apt update fails due to Release file validity date error – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026 Affected versions: Ubuntu 26.04 LTS 📖 ~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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