<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:content="http://purl.org/rss/1.0/modules/content/"><channel><title>Yggdrasil - CraftedSignal Threat Feed</title><link>https://feed.craftedsignal.io/vendors/yggdrasil/</link><description>Trending threats, MITRE ATT&amp;CK coverage, and detection metadata. Fed continuously.</description><generator>Hugo</generator><language>en</language><managingEditor>hello@craftedsignal.io</managingEditor><webMaster>hello@craftedsignal.io</webMaster><lastBuildDate>Fri, 31 Jul 2026 03:33:40 +0000</lastBuildDate><atom:link href="https://feed.craftedsignal.io/vendors/yggdrasil/feed.xml" rel="self" type="application/rss+xml"/><item><title>Argument Injection Vulnerability in yggdrasil-worker-package-manager</title><link>https://feed.craftedsignal.io/briefs/2026-07-yggdrasil-apt-injection/</link><pubDate>Fri, 31 Jul 2026 03:33:40 +0000</pubDate><author>hello@craftedsignal.io</author><guid isPermaLink="true">https://feed.craftedsignal.io/briefs/2026-07-yggdrasil-apt-injection/</guid><description>An argument injection vulnerability in the APT backend of yggdrasil-worker-package-manager allows local attackers to manipulate apt-get command-line arguments to achieve root-level code execution.</description><content:encoded><![CDATA[<p>CVE-2026-18157 identifies a critical argument injection vulnerability within the yggdrasil-worker-package-manager's APT backend. The vulnerability stems from improper validation of package names passed to the underlying apt-get utility. A local attacker who has already gained low-privileged access to the system can provide a maliciously crafted package name - specifically one beginning with a hyphen - which the application fails to distinguish from legitimate command-line flags.</p>
<p>When processed, these injected strings are interpreted by apt-get as command-line options rather than arguments. By leveraging specific apt-get options that permit the execution of arbitrary scripts or custom configurations (such as pre- or post-installation hooks), an attacker can achieve code execution with root privileges. This vulnerability is significant as it provides a direct path from low-privileged system access to a full root-level compromise of the host's integrity, confidentiality, and availability.</p>
<h2 id="attack-chain">Attack Chain</h2>
<ol>
<li>Attacker gains initial low-privileged access to the target host environment.</li>
<li>Attacker identifies that the system utilizes yggdrasil-worker-package-manager for automated package operations.</li>
<li>Attacker crafts a package name starting with a hyphen (e.g., &quot;-oDir::Etc::SourceList=/tmp/malicious_list&quot;).</li>
<li>Attacker triggers a package installation or update request via the vulnerable worker interface.</li>
<li>yggdrasil-worker-package-manager constructs an apt-get command string incorporating the malicious input without proper sanitization.</li>
<li>apt-get executes the command, interpreting the injected hyphenated string as a valid operational option.</li>
<li>apt-get hooks or configuration directives are manipulated to execute arbitrary commands.</li>
<li>Attacker achieves remote code execution or privilege escalation to the root user.</li>
</ol>
<h2 id="impact">Impact</h2>
<p>Successful exploitation of this vulnerability results in full system compromise. As the affected worker process interacts with the system's package manager, the resulting code execution occurs with root-level privileges. This enables an attacker to install persistent backdoors, exfiltrate sensitive data, manipulate system binaries, or disable security auditing mechanisms. The impact is categorized as high, with a CVSS v3.1 base score of 7.8, reflecting the potential for total system takeover by an authenticated local actor.</p>
<h2 id="recommendation">Recommendation</h2>
<p>Prioritized actions for detection and mitigation:</p>
<ul>
<li>Patch or update yggdrasil-worker-package-manager to the version that includes sanitization for input passed to apt-get.</li>
<li>Audit logs for execution of apt-get processes with anomalous command-line flags that suggest option injection (e.g., usage of &quot;-o&quot; or &quot;--option&quot; flags that reference temp or user-controlled directories).</li>
<li>Enforce strict least-privilege policies for accounts authorized to trigger package manager operations via the yggdrasil worker.</li>
<li>Monitor for unexpected parent-child process relationships where the worker service spawns apt-get with non-standard command-line arguments.</li>
</ul>
]]></content:encoded><category domain="severity">high</category><category domain="type">advisory</category><category>privilege-escalation</category><category>linux</category><category>cve-2026-18157</category></item></channel></rss>