Linux: Double Free
CVE-2024-56699 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 c1489651071ab1be46d2af1da8adb15c9fc3c069, 371bd905599d18da62d75e3974acbf6a41e315c7, c4a585e952ca403a370586d3f16e8331a7564901 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 0.21% 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 c1489651071ab1be46d2af1da8adb15c9fc3c069 or 371bd905599d18da62d75e3974acbf6a41e315c7 or c4a585e952ca403a370586d3f16e8331a7564901, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.11.11 or 6.12.2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 6ee600bfbe0f818ffb7748d99e9b0c89d0d9f02a up to, but not including, c1489651071ab1be46d2af1da8adb15c9fc3c069; 6ee600bfbe0f818ffb7748d99e9b0c89d0d9f02a up to, but not including, 371bd905599d18da62d75e3974acbf6a41e315c7; 6ee600bfbe0f818ffb7748d99e9b0c89d0d9f02a up to, but not including, c4a585e952ca403a370586d3f16e8331a7564901; 6.9 | c1489651071ab1be46d2af1da8adb15c9fc3c069, 371bd905599d18da62d75e3974acbf6a41e315c7, c4a585e952ca403a370586d3f16e8331a7564901 |
| Linux | Linux Kernel | 6.9 up to, but not including, 6.11.11; 6.12 up to, but not including, 6.12.2 | 6.11.11, 6.12.2 |
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: s390/pci: Fix potential double remove of hotplug slot In commit 6ee600bfbe0f ("s390/pci: remove hotplug slot when releasing the device") the zpci_exit_slot() was moved from zpci_device_reserved() to zpci_release_device() with the intention of keeping the hotplug slot around until the device is actually removed. Now zpci_release_device() is only called once all references are dropped. Since the zPCI subsystem only drops its reference once the device is in the reserved state it follows that zpci_release_device() must only deal with devices in the reserved state. Despite that it contains code to tear down from both configured and standby state. For the standby case this already includes the removal of the hotplug slot so would cause a double removal if a device was ever removed in either configured or standby state. Instead of causing a potential double removal in a case that should never happen explicitly WARN_ON() if a device in non-reserved state is released and get rid of the dead code cases.
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
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
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