Authentication Bypass and Linux Kernel Flaws Under Active Exploitation

Three critical vulnerabilities have been confirmed as actively exploited in the wild, triggering urgent additions to CISA’s Known Exploited Vulnerabilities catalogue. CVE-2023-49105, an authentication bypass in ownCloud, allows attackers to access, modify, or delete files without credentials when only a username is known. Despite being disclosed in 2023, active exploitation has only now escalated. CVE-2026-53362, a Linux kernel privilege escalation flaw affecting major distributions and cloud infrastructure, enables attackers to gain full administrative control from limited footholds. Two openssl_encrypt vulnerabilities (CVE-2026-81702 and CVE-2026-81707) permit sophisticated identity spoofing attacks, compromising encrypted communications and fingerprint verification mechanisms. For UK small businesses, the regulatory exposure is concrete: unauthenticated file access triggers UK GDPR breach notification obligations, and running unpatched software with confirmed active exploits undermines defensibility to the ICO. This episode provides specific, actionable steps to verify patch status with IT providers and MSPs, establish documented accountability, and meet Cyber Essentials compliance requirements within the scheme’s fourteen-day patching window for high-severity actively exploited CVEs.

Chapters

• Introduction Corrine introduces three actively exploited vulnerabilities confirmed by CISA, including an authentication bypass requiring only a username to compromise systems.
• ownCloud Authentication Bypass: CVE-2023-49105 Analysis of CVE-2023-49105, an ownCloud vulnerability disclosed in 2023 but now under active exploitation, allowing unauthenticated file access, modification, and deletion with UK GDPR breach implications.
• Call to Action Request to follow, rate, review, and share the podcast to support ongoing critical vulnerability coverage for UK small businesses.
• Linux Kernel Privilege Escalation: CVE-2026-53362 Examination of CVE-2026-53362, a Linux kernel IPv6 privilege escalation flaw affecting cloud infrastructure, hosting providers, and network appliances, with Cyber Essentials compliance implications.
• openssl_encrypt Identity Spoofing: CVE-2026-81702 and CVE-2026-81707 Coverage of two critical openssl_encrypt vulnerabilities enabling public key substitution and fingerprint verification manipulation in encrypted communications and identity verification systems.
• Business Case and Pre-Friday Actions Regulatory, competitive, and procurement arguments for addressing these vulnerabilities, with five specific actions to complete before end of week, including MSP accountability and patch documentation.
• Conclusion Closing remarks emphasising the three-year gap between CVE-2023-49105 disclosure and active exploitation, urging immediate action on clear intelligence guidance.

Links

• https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• https://owncloud.com/security-advisories/
• https://www.ico.org.uk/for-organisations/guide-to-data-protection/guide-to-the-general-data-protection-regulation-gdpr/personal-data-breaches/
• https://www.ncsc.gov.uk/cyberessentials/overview