Ethical Hacking News
A new zero-day bug in Windows has been discovered, allowing an authorized attacker to leak a memory address from a remote ALPC port. The US Cybersecurity and Infrastructure Security Agency (CISA) has flagged the vulnerability as a "frequent attack vector for malicious cyber actors," and Microsoft has pushed a patch to address the issue. However, concerns remain about whether other components may be involved in an exploit chain, highlighting the importance of rapid patching and staying informed about newly disclosed vulnerabilities.
Microsoft has discovered a new zero-day bug in Windows (CVE-2026-20805) that allows an attacker to leak memory addresses from a remote port. The vulnerability is classified as medium-severity with a 5.5 CVSS rating, allowing attackers to potentially execute malicious code with elevated privileges. The CISA has added the bug to its list of Known Exploited Vulnerabilities catalog and warned federal agencies must implement the fix by February 3. Other components may be involved in an exploit chain, making it challenging for network defenders to proactively threat-hunt for related activity. Staying informed about newly disclosed vulnerabilities and applying patches promptly is crucial to prevent attacks.
Microsoft has once again reminded users of the importance of keeping their operating systems up-to-date, as a newly disclosed zero-day bug in Windows has caught the attention of the US Cybersecurity and Infrastructure Security Agency (CISA). The CVE-2026-20805 bug, which was discovered by Microsoft's own threat intelligence team, allows an authorized attacker to leak a memory address from a remote ALPC port. This vulnerability, classified as medium-severity with a 5.5 CVSS rating, has significant implications for federal agencies and organizations that rely on Windows as their primary operating system.
According to Dustin Childs, the Head of Threat Awareness at Trend Micro's Zero Day Initiative, "Presumably, threat actors would then use the address in the next stage of their exploit chain – probably gaining arbitrary code execution." This means that if an attacker is able to exploit this vulnerability, they could potentially execute malicious code with elevated privileges on a system. The potential impact of such an attack is significant, as it could allow attackers to gain unauthorized access to sensitive data or disrupt critical systems.
The CISA has already taken action to address the vulnerability, adding CVE-2026-20805 to its list of Known Exploited Vulnerabilities catalog. This means that federal agencies must implement the fix by February 3, as the agency warned that this type of vulnerability is a "frequent attack vector for malicious cyber actors and poses significant risks to the federal enterprise."
While Microsoft has pushed a patch for the bug, there is still concern about whether other components may be involved in an exploit chain. Kev Breen, senior director of cyber threat research at Immersive, noted that "Vulnerabilities of this nature are commonly used to undermine Address Space Layout Randomization (ASLR), a core operating system security control designed to protect against buffer overflows and other memory-manipulation exploits." By revealing where code resides in memory, this vulnerability can be chained with a separate code execution flaw, transforming a complex and unreliable exploit into a practical and repeatable attack.
The fact that Microsoft has not disclosed which other components may be involved in an exploit chain significantly limits the ability of network defenders to proactively threat-hunt for related activity. As a result, rapid patching currently remains the only effective mitigation, according to Breen. The lack of transparency from Microsoft on this issue highlights the importance of keeping systems up-to-date and applying patches promptly.
In addition to CVE-2026-20805, two other publicly known bugs have been disclosed: CVE-2023-31096, a 7.8-rated elevation of privilege flaw in third-party Agere Modem drivers that ship with supported Windows versions, and CVE-2026-20952 (CVSS 7.7) and CVE-2026-20953 (CVSS 7.4), both use-after-free Office flaws that can allow an unauthorized attacker to execute code locally.
The release of these patches highlights the importance of staying informed about newly disclosed vulnerabilities and applying them promptly. As Childs noted, "Another month with Preview Pane exploit vectors in an Office bug... While we are still unaware of any exploitation of these bugs, they keep adding up. It's only a matter of time until threat actors find a way to use these types of bugs in their exploits."
In conclusion, the newly disclosed Windows 0-day bug serves as a reminder of the importance of keeping systems up-to-date and applying patches promptly. As organizations continue to navigate the complex landscape of cybersecurity threats, it is essential that they prioritize patching and stay informed about newly disclosed vulnerabilities.
Related Information:
https://www.ethicalhackingnews.com/articles/A-Patching-Paradox-Unpacking-the-Windows-0-Day-Bug-and-its-Implications-for-Cybersecurity-ehn.shtml
https://go.theregister.com/feed/www.theregister.com/2026/01/14/patch_tuesday_january_2026/
Published: Wed Jan 14 00:55:23 2026 by llama3.2 3B Q4_K_M
