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CVE-2026-49237 Canonical CVE debrief

This CVE documents an incomplete remediation of CVE-2025-5199 in Canonical Multipass for macOS. Version 1.16.0 corrected ownership of the multipassd daemon binary to root:wheel, but left five auxiliary binaries in /Library/Application Support/com.canonical.multipass/bin/ owned by the installing user and writable. The root LaunchDaemon (com.canonical.multipassd.plist) configures a PATH that prioritizes this user-writable directory and invokes these binaries by bare name. A local attacker can replace an auxiliary binary (e.g., qemu-img) with a malicious wrapper; when the daemon triggers it during routine operations such as `multipass launch`, the attacker's code executes with root privileges. This represents a local privilege escalation via writable auxiliary executables in a privileged PATH.

Vendor
Canonical
Product
Multipass
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-28
Original CVE updated
2026-06-01
Advisory published
2026-05-28
Advisory updated
2026-06-01

Who should care

Organizations and individuals running Canonical Multipass on macOS systems, particularly multi-user environments or systems where untrusted users have local access. System administrators responsible for macOS endpoint security and developers using Multipass for local virtualization workloads.

Technical summary

The vulnerability stems from an incomplete security update. While the main daemon binary ownership was corrected in version 1.16.0, five co-located auxiliary binaries remained with user-writable permissions. The root-privileged LaunchDaemon's PATH configuration prioritizes the directory containing these binaries and invokes them by unqualified name. This allows a local attacker with user privileges to substitute a malicious binary that will be executed by root during normal daemon operations, achieving privilege escalation. The attack requires local access and write permissions to the Multipass bin directory, with no user interaction needed for exploitation once the malicious binary is in place.

Defensive priority

HIGH

Recommended defensive actions

  • Upgrade to Canonical Multipass 1.16.3 or later for macOS.
  • Verify that all binaries in /Library/Application Support/com.canonical.multipass/bin/ are owned by root:wheel and not writable by group or other.
  • Review LaunchDaemon configuration for PATH environment variable hardening.
  • Audit for unexpected modifications to auxiliary binaries (multipass, qemu-img, qemu-system-aarch64, qemu-system-x86_64, sshfs_server).
  • If immediate patching is not possible, restrict local access to the affected system and monitor for unauthorized file modifications in the Multipass bin directory.

Evidence notes

NVD record published 2026-05-28T14:16:24.270Z; modified 2026-05-28T18:00:33.730Z. Advisory reference from [email protected] links to GitHub Security Advisory GHSA-r2xg-x32f-23c5. CVSS 3.1 vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H yields 7.8 (HIGH). CWE-276 (Incorrect Default Permissions) cited.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-49237 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-49237

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-49237 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-49237

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.