CVE-2026-49418
When msync(MS_INVALIDATE) is called on a mapping of an unmanaged device object, the physical pages in the mapping range are marked invalid but remain in the pager's page list. A subsequent page fault will cause the fault handler to re-insert the page into the object's list. This corrupts the list, and on object destruction the page is freed twice. An unprivileged local user with access to a device that provides memory-mapped I/O can trigger a use-after-free in the kernel, though this is limited to a pool of objects ("fictitious pages") that are never recycled for a different purpose. It may be possible to exploit this to escalate privileges.
Executive briefing
The source record describes: When msync(MS_INVALIDATE) is called on a mapping of an unmanaged device object, the physical pages in the mapping range are marked invalid but remain in the pager's page list. A subsequent page fault will cause the fault handler to re-insert the page into the object's list. This corrupts the list, and on object destruction the page is freed twice. An unprivileged local user with access to a device that provides memory-mapped I/O can trigger a use-after-free in the kernel, though this is limited to a pool of objects ("fictitious pages") that are never recycled for a different purpose. It may be possible to exploit this to escalate privileges. The practical risk depends on whether an affected product/version is present, reachable and configured in an exploitable way. Review the affected-product evidence and linked vendor advisories before assigning exposure status.
Evidence confidence: Moderate Evidence-derived, not an exploitability verdict
Severity & attack characteristics
CVSS vector:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Technical explanation & impact
The technical mechanism is not expanded beyond the source description unless a referenced advisory supplies additional evidence. Read the linked vendor/CERT advisories for root-cause detail.
Potential impact must be interpreted from the published CVSS impact metrics and the affected component. A CVSS impact score is not proof that a particular asset is exploitable.
Weakness classification
CWE-416Affected products and versions
Products below are parsed from NVD vulnerable CPE configuration entries. Version boundaries are shown as published; verify applicability with the vendor.
| Vendor | Product | Version evidence |
|---|---|---|
| freebsd | freebsd | CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.3 · CPE version 14.4 · CPE version 14.4 · CPE version 14.4 · CPE version 14.4 · CPE version 14.4 · CPE version 14.4 · CPE version 14.4 · CPE version 14.4 · CPE version 15.0 · CPE version 15.0 · CPE version 15.0 · CPE version 15.0 · CPE version 15.0 · CPE version 15.0 · CPE version 15.0 · CPE version 15.0 · CPE version 15.0 · CPE version 15.0 · CPE version 15.0 · CPE version 15.1 · CPE version 15.1 · CPE version 15.1 |
Remediation & validation
- Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
- Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
- Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
- Validate the remediation with a version check and vulnerability rescan, then retain change evidence.
No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.
Vendor advisories, patches & exploit references
- https://security.freebsd.org/advisories/FreeBSD-SA-26:37.vm.asc ADVISORY secteam@freebsd.org