Skip to main content
Mallory
Critical

Boxlite read-only volume remount bypass

IdentifiersCVE-2026-46695CWE-284· Improper Access Control

CVE-2026-46695 is a critical sandbox-escape vulnerability in Boxlite prior to version 0.9.0. Boxlite runs untrusted code inside lightweight virtual machines and OCI containers, and affected versions mounted host directories shared via virtiofs as guest-side read-only by relying on the guest to set MS_RDONLY. However, the default guest capability set still included CAP_SYS_ADMIN. As a result, malicious code running inside the sandbox could remount an ostensibly read-only shared directory as read-write using a remount operation such as mount -o remount,rw <path>, then write through that share to the host filesystem. This breaks Boxlite’s advertised read-only isolation guarantees and allows arbitrary write operations against directories that should have remained read-only. The issue was fixed in v0.9.0 by enforcing read-only at the hypervisor level via krun_add_virtiofs3 and by dropping CAP_SYS_ADMIN from the default guest capability set.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows untrusted code executing inside a Boxlite sandbox to bypass the read-only restriction on shared host directories and perform arbitrary writes to the host filesystem through the remounted virtiofs share. This constitutes a sandbox escape and can compromise integrity of host data, expose or alter sensitive files reachable through the shared path, and potentially enable broader host compromise depending on what directories are exposed. Supporting content indicates critical severity, with high confidentiality, integrity, and availability impact.

Mitigation

If you can’t patch tonight, do this now.

The available content states there is no workaround. If immediate upgrade is not possible, risk can only be reduced operationally by avoiding exposure of sensitive host directories to untrusted sandboxes, minimizing or eliminating shared virtiofs mounts, and ensuring sandboxed workloads do not retain CAP_SYS_ADMIN-equivalent capability to remount filesystems. These measures are mitigations only; the documented fix is to upgrade to 0.9.0 or later.

Remediation

Patch, then assume compromise.

Upgrade Boxlite to version 0.9.0 or later. The patched release enforces read-only semantics at the hypervisor level for virtiofs shares via krun_add_virtiofs3 and removes CAP_SYS_ADMIN from the default guest capability set, eliminating the guest-side remount bypass described in the advisory.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
boxlite-aiBoxliteapplication
boxlite-aiBoxlite-Cliapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity6

Community discussion across Reddit, Mastodon, and other social sources.