{"id":"CVE-2026-46695","aliases":["RUSTSEC-2026-0147","GHSA-g6ww-w5j2-r7x3","GO-2026-5392","PYSEC-2026-299"],"title":"Read-only volume remount bypass via guest CAP_SYS_ADMIN","summary":"Read-only volume remount bypass via guest CAP_SYS_ADMIN","severity":"critical","cvss":10,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","vendor":"boxlite","product":"boxlite","ecosystem":"rust","affected":["boxlite >= 0.0.0-0, < 0.9.0"],"patched":["boxlite 0.9.0"],"published":"2026-05-16","updated":"2026-10-12","sourceUpdated":"2026-10-12T18:00:13.061473890Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/RUSTSEC-2026-0147","references":[{"url":"https://crates.io/crates/boxlite"},{"url":"https://rustsec.org/advisories/RUSTSEC-2026-0147.html"},{"url":"https://github.com/boxlite-ai/boxlite/pull/454"},{"url":"https://github.com/boxlite-ai/boxlite/pull/454"},{"url":"https://github.com/boxlite-ai/boxlite/security/advisories/GHSA-g6ww-w5j2-r7x3"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46695"},{"url":"https://github.com/boxlite-ai/boxlite"},{"url":"https://github.com/boxlite-ai/boxlite/releases/tag/v0.9.0"}],"tags":["osv","rust","pip"],"epss":0.00289,"epssPercentile":0.21327,"ingestedAt":"2026-09-12T03:13:01.694Z","slug":"CVE-2026-46695","body":"## Overview\n\nAffected versions of `boxlite` mount host directories shared via virtiofs\nas guest-side read-only by setting `MS_RDONLY` from the guest. Because the\ndefault guest capability set included `CAP_SYS_ADMIN`, untrusted code\nrunning inside a sandbox could execute `mount -o remount,rw <path>` to\nre-flag the share as read-write and then write through to the host\nfilesystem — fully escaping the read-only contract `boxlite` advertised\nto callers.\n\nThe fix in v0.9.0 enforces read-only at the hypervisor level via\n`krun_add_virtiofs3` (so the guest's `MS_RDONLY` is no longer the\nauthoritative gate) and drops `CAP_SYS_ADMIN` from the default guest\ncapability set (matching Docker's defaults).\n\nThis is a sandbox-escape bug: `boxlite` is a sandboxing runtime, so the\nread-only invariant is part of its security contract. CVSS rated 10.0 by\nthe upstream advisory.\n\n## Affected packages\n\n- `boxlite >= 0.0.0-0, < 0.9.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `boxlite 0.9.0`","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":55,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}