Linux: Double Free
CVE-2026-53067 is a high-severity double free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 175717cfc06cab79f84cd037d66dda1b8564cd9e, 3c25587fbf8797b92090b064a6d239a873e55fb1, 1cba96c0a795124c3229293ed7b5b5765e66f259 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 175717cfc06cab79f84cd037d66dda1b8564cd9e or 3c25587fbf8797b92090b064a6d239a873e55fb1 or 1cba96c0a795124c3229293ed7b5b5765e66f259, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.33 or 7.0.10, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 1c3b002c6bf684b445a7107609979bca5f21bc03 up to, but not including, 175717cfc06cab79f84cd037d66dda1b8564cd9e; 1c3b002c6bf684b445a7107609979bca5f21bc03 up to, but not including, 3c25587fbf8797b92090b064a6d239a873e55fb1; 1c3b002c6bf684b445a7107609979bca5f21bc03 up to, but not including, 1cba96c0a795124c3229293ed7b5b5765e66f259; 6.17 | 175717cfc06cab79f84cd037d66dda1b8564cd9e, 3c25587fbf8797b92090b064a6d239a873e55fb1, 1cba96c0a795124c3229293ed7b5b5765e66f259 |
| Linux | Linux Kernel | 6.17 up to, but not including, 6.18.33; 6.19 up to, but not including, 7.0.10 | 6.18.33, 7.0.10 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: PCI: endpoint: pci-ep-msi: Fix error unwind and prevent double alloc pci_epf_alloc_doorbell() stores the allocated doorbell message array in epf->db_msg/epf->num_db before requesting MSI vectors. If MSI allocation fails, the array is freed but the EPF state may still point to freed memory. Clear epf->db_msg and epf->num_db on the MSI allocation failure path so that later cleanup cannot double-free the array and callers can retry allocation. Also return -EBUSY when doorbells have already been allocated to prevent leaking or overwriting an existing allocation.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Double Free
The product calls free() twice on the same memory address.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Use a static analysis tool to find double free instances.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Double Free vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
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