Linux: Use After Free
CVE-2024-47748 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 0c170b1e918b9afac25e2bbd01eaa2bfc0ece8c0, 927a2580208e0f9b0b47b08f1c802b7233a7ba3c, ec5f1b54ceb23475049ada6e7a43452cf4df88d1 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 0c170b1e918b9afac25e2bbd01eaa2bfc0ece8c0 or 927a2580208e0f9b0b47b08f1c802b7233a7ba3c or ec5f1b54ceb23475049ada6e7a43452cf4df88d1 or ca64edd7ae93402af2596a952e0d94d545e2b9c0, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.227 or 5.15.168 or 6.1.113 or 6.6.54, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 2cf1ba9a4d15cb78b96ea97f727b93382c3f9a60 up to, but not including, 0c170b1e918b9afac25e2bbd01eaa2bfc0ece8c0; 2cf1ba9a4d15cb78b96ea97f727b93382c3f9a60 up to, but not including, 927a2580208e0f9b0b47b08f1c802b7233a7ba3c; 2cf1ba9a4d15cb78b96ea97f727b93382c3f9a60 up to, but not including, ec5f1b54ceb23475049ada6e7a43452cf4df88d1; 2cf1ba9a4d15cb78b96ea97f727b93382c3f9a60 up to, but not including, ca64edd7ae93402af2596a952e0d94d545e2b9c0; 2cf1ba9a4d15cb78b96ea97f727b93382c3f9a60 up to, but not including, fae9b1776f53aab93ab345bdbf653b991aed717d; 2cf1ba9a4d15cb78b96ea97f727b93382c3f9a60 up to, but not including, 7cf2fb51175cafe01df8c43fa15a06194a59c6e2; 2cf1ba9a4d15cb78b96ea97f727b93382c3f9a60 up to, but not including, 02e9e9366fefe461719da5d173385b6685f70319; 5.9 | 0c170b1e918b9afac25e2bbd01eaa2bfc0ece8c0, 927a2580208e0f9b0b47b08f1c802b7233a7ba3c, ec5f1b54ceb23475049ada6e7a43452cf4df88d1, ca64edd7ae93402af2596a952e0d94d545e2b9c0, fae9b1776f53aab93ab345bdbf653b991aed717d, 7cf2fb51175cafe01df8c43fa15a06194a59c6e2 |
| Linux | Linux Kernel | 5.9 up to, but not including, 5.10.227; 5.11 up to, but not including, 5.15.168; 5.16 up to, but not including, 6.1.113; 6.2 up to, but not including, 6.6.54; 6.7 up to, but not including, 6.10.13; 6.11 up to, but not including, 6.11.2 | 5.10.227, 5.15.168, 6.1.113, 6.6.54, 6.10.13, 6.11.2 |
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.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: vhost_vdpa: assign irq bypass producer token correctly We used to call irq_bypass_unregister_producer() in vhost_vdpa_setup_vq_irq() which is problematic as we don't know if the token pointer is still valid or not. Actually, we use the eventfd_ctx as the token so the life cycle of the token should be bound to the VHOST_SET_VRING_CALL instead of vhost_vdpa_setup_vq_irq() which could be called by set_status(). Fixing this by setting up irq bypass producer's token when handling VHOST_SET_VRING_CALL and un-registering the producer before calling vhost_vring_ioctl() to prevent a possible use after free as eventfd could have been released in vhost_vring_ioctl(). And such registering and unregistering will only be done if DRIVER_OK is set.
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/02e9e9366fefe461719da5d173385b6685f70319
- git.kernel.org/stable/c/0c170b1e918b9afac25e2bbd01eaa2bfc0ece8c0
- git.kernel.org/stable/c/7cf2fb51175cafe01df8c43fa15a06194a59c6e2
- git.kernel.org/stable/c/927a2580208e0f9b0b47b08f1c802b7233a7ba3c
- git.kernel.org/stable/c/ca64edd7ae93402af2596a952e0d94d545e2b9c0
- git.kernel.org/stable/c/ec5f1b54ceb23475049ada6e7a43452cf4df88d1
- git.kernel.org/stable/c/fae9b1776f53aab93ab345bdbf653b991aed717d
Other references
Recent Use After Free vulnerabilities
- 7.0 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.