Linux: Use After Free
CVE-2024-58083 is a high-severity use after 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 5cce2ed69b00e022b5cdf0c49c82986abd2941a8, 09d50ccf0b2d739db4a485b08afe7520a4402a63, 7c4899239d0f70f88ac42665b3da51678d122480 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 0.22% 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 5cce2ed69b00e022b5cdf0c49c82986abd2941a8 or 09d50ccf0b2d739db4a485b08afe7520a4402a63 or 7c4899239d0f70f88ac42665b3da51678d122480 or d817e510662fd1c9797952408d94806f97a5fffd, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.15 or 4.20 or 5.4.291 or 5.10.235, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c up to, but not including, 5cce2ed69b00e022b5cdf0c49c82986abd2941a8; 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c up to, but not including, 09d50ccf0b2d739db4a485b08afe7520a4402a63; 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c up to, but not including, 7c4899239d0f70f88ac42665b3da51678d122480; 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c up to, but not including, d817e510662fd1c9797952408d94806f97a5fffd; 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c up to, but not including, 125da53b3c0c9d7f58353aea0076e9efd6498ba7; 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c up to, but not including, f2f805ada63b536bc192458a7098388286568ad4; 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c up to, but not including, ca8da90ed1432ff3d000de4f1e2275d4e7d21b96; 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c up to, but not including, 1e7381f3617d14b3c11da80ff5f8a93ab14cfc46; and 7 more ranges | 5cce2ed69b00e022b5cdf0c49c82986abd2941a8, 09d50ccf0b2d739db4a485b08afe7520a4402a63, 7c4899239d0f70f88ac42665b3da51678d122480, d817e510662fd1c9797952408d94806f97a5fffd, 125da53b3c0c9d7f58353aea0076e9efd6498ba7, f2f805ada63b536bc192458a7098388286568ad4 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Linux | Linux Kernel | 4.14.120 up to, but not including, 4.15; 4.19.44 up to, but not including, 4.20; 5.0.17 up to, but not including, 5.4.291; 5.5 up to, but not including, 5.10.235; 5.11 up to, but not including, 5.15.179; 5.16 up to, but not including, 6.1.129; 6.2 up to, but not including, 6.6.78; 6.7 up to, but not including, 6.12.14; and 1 more ranges | 4.15, 4.20, 5.4.291, 5.10.235, 5.15.179, 6.1.129 |
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 CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: KVM: Explicitly verify target vCPU is online in kvm_get_vcpu() Explicitly verify the target vCPU is fully online _prior_ to clamping the index in kvm_get_vcpu(). If the index is "bad", the nospec clamping will generate '0', i.e. KVM will return vCPU0 instead of NULL. In practice, the bug is unlikely to cause problems, as it will only come into play if userspace or the guest is buggy or misbehaving, e.g. KVM may send interrupts to vCPU0 instead of dropping them on the floor. However, returning vCPU0 when it shouldn't exist per online_vcpus is problematic now that KVM uses an xarray for the vCPUs array, as KVM needs to insert into the xarray before publishing the vCPU to userspace (see commit c5b077549136 ("KVM: Convert the kvm->vcpus array to a xarray")), i.e. before vCPU creation is guaranteed to succeed. As a result, incorrectly providing access to vCPU0 will trigger a use-after-free if vCPU0 is dereferenced and kvm_vm_ioctl_create_vcpu() bails out of vCPU creation due to an error and frees vCPU0. Commit afb2acb2e3a3 ("KVM: Fix vcpu_array[0] races") papered over that issue, but in doing so introduced an unsolvable teardown conundrum. Preventing accesses to vCPU0 before it's fully online will allow reverting commit afb2acb2e3a3, without re-introducing the vcpu_array[0] UAF race.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/09d50ccf0b2d739db4a485b08afe7520a4402a63
- git.kernel.org/stable/c/125da53b3c0c9d7f58353aea0076e9efd6498ba7
- git.kernel.org/stable/c/1e7381f3617d14b3c11da80ff5f8a93ab14cfc46
- git.kernel.org/stable/c/5cce2ed69b00e022b5cdf0c49c82986abd2941a8
- git.kernel.org/stable/c/7c4899239d0f70f88ac42665b3da51678d122480
- git.kernel.org/stable/c/ca8da90ed1432ff3d000de4f1e2275d4e7d21b96
- git.kernel.org/stable/c/d817e510662fd1c9797952408d94806f97a5fffd
- git.kernel.org/stable/c/f2f805ada63b536bc192458a7098388286568ad4
Other references
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
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