CVE-2026-49237: Incorrect default permissions in Canonical Multipass
An issue was discovered in Canonical Multipass for macOS before version 1.16.3 due to an incomplete fix for CVE-2025-5199. While the patch in version 1.16.0 updated the ownership of the multipassd daemon binary to root:wheel, five co-located binaries (multipass, qemu-img, qemu-system-aarch64, qemu-system-x86_64, and sshfs_server) in /Library/Application Support/com.canonical.multipass/bin/ retain ownership by the installing user and remain writable. Because the root LaunchDaemon (com.canonical.multipassd.plist) configures a PATH environment variable that prioritizes this user-writable directory and invokes these auxiliary binaries by their bare names, a local attacker can replace an auxiliary binary (such as qemu-img) with a malicious wrapper. When the root daemon subsequently triggers the binary during routine execution (e.g., via multipass launch), the malicious code executes with root privileges, leading to local privilege escalation.
AI Analysis
Technical Summary
This vulnerability in Canonical Multipass for macOS involves incorrect default permissions on five auxiliary binaries located in /Library/Application Support/com.canonical.multipass/bin/. Although the main daemon binary's ownership was corrected to root:wheel in version 1.16.0, these auxiliary binaries remain writable by the installing user. The root LaunchDaemon (com.canonical.multipassd.plist) sets a PATH environment variable that prioritizes this directory and calls these binaries by name. A local attacker with write access can replace an auxiliary binary with a malicious wrapper, which the root daemon then executes with elevated privileges, resulting in local privilege escalation.
Potential Impact
Successful exploitation allows a local attacker to execute arbitrary code with root privileges on the affected system. This can lead to full system compromise, including unauthorized access, modification, or destruction of data and system configurations.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict local user write permissions to the directory /Library/Application Support/com.canonical.multipass/bin/ and its binaries to prevent unauthorized modification. Monitor for updates from Canonical regarding a complete fix addressing this issue.
CVE-2026-49237: Incorrect default permissions in Canonical Multipass
Description
An issue was discovered in Canonical Multipass for macOS before version 1.16.3 due to an incomplete fix for CVE-2025-5199. While the patch in version 1.16.0 updated the ownership of the multipassd daemon binary to root:wheel, five co-located binaries (multipass, qemu-img, qemu-system-aarch64, qemu-system-x86_64, and sshfs_server) in /Library/Application Support/com.canonical.multipass/bin/ retain ownership by the installing user and remain writable. Because the root LaunchDaemon (com.canonical.multipassd.plist) configures a PATH environment variable that prioritizes this user-writable directory and invokes these auxiliary binaries by their bare names, a local attacker can replace an auxiliary binary (such as qemu-img) with a malicious wrapper. When the root daemon subsequently triggers the binary during routine execution (e.g., via multipass launch), the malicious code executes with root privileges, leading to local privilege escalation.
CVSS v3.1
Score 7.8high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in Canonical Multipass for macOS involves incorrect default permissions on five auxiliary binaries located in /Library/Application Support/com.canonical.multipass/bin/. Although the main daemon binary's ownership was corrected to root:wheel in version 1.16.0, these auxiliary binaries remain writable by the installing user. The root LaunchDaemon (com.canonical.multipassd.plist) sets a PATH environment variable that prioritizes this directory and calls these binaries by name. A local attacker with write access can replace an auxiliary binary with a malicious wrapper, which the root daemon then executes with elevated privileges, resulting in local privilege escalation.
Potential Impact
Successful exploitation allows a local attacker to execute arbitrary code with root privileges on the affected system. This can lead to full system compromise, including unauthorized access, modification, or destruction of data and system configurations.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict local user write permissions to the directory /Library/Application Support/com.canonical.multipass/bin/ and its binaries to prevent unauthorized modification. Monitor for updates from Canonical regarding a complete fix addressing this issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- canonical
- Date Reserved
- 2026-05-28T12:03:02.295Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a184ec2e29bf47b50f3f921
Added to database: 5/28/2026, 2:18:42 PM
Last enriched: 5/28/2026, 2:35:12 PM
Last updated: 5/29/2026, 7:31:07 AM
Views: 8
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