Linux: Use After Free
CVE-2023-53084 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 684c7372bbd6447c2e86a2a84e97a1478604d21f, 5cfb617967b05f8f27e862c97db1fabd8485f4db, dede8c14a37a7ac458f9add56154a074ed78e7cf 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 684c7372bbd6447c2e86a2a84e97a1478604d21f or 5cfb617967b05f8f27e862c97db1fabd8485f4db or dede8c14a37a7ac458f9add56154a074ed78e7cf or 77d26c824aa5a7e0681ef1d5b75fe538d746addc, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10 or 5.10.176 or 5.15.104 or 6.1.21, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f49a51bfdc8ea717c97ccd4cc98b7e6daaa5553a up to, but not including, 684c7372bbd6447c2e86a2a84e97a1478604d21f; f49a51bfdc8ea717c97ccd4cc98b7e6daaa5553a up to, but not including, 5cfb617967b05f8f27e862c97db1fabd8485f4db; f49a51bfdc8ea717c97ccd4cc98b7e6daaa5553a up to, but not including, dede8c14a37a7ac458f9add56154a074ed78e7cf; f49a51bfdc8ea717c97ccd4cc98b7e6daaa5553a up to, but not including, 77d26c824aa5a7e0681ef1d5b75fe538d746addc; f49a51bfdc8ea717c97ccd4cc98b7e6daaa5553a up to, but not including, ee9adb7a45516cfa536ca92253d7ae59d56db9e4; 4655afcf0e3874af03afff8c8704b52350bdba47; 5.9.5 up to, but not including, 5.10; 5.10 | 684c7372bbd6447c2e86a2a84e97a1478604d21f, 5cfb617967b05f8f27e862c97db1fabd8485f4db, dede8c14a37a7ac458f9add56154a074ed78e7cf, 77d26c824aa5a7e0681ef1d5b75fe538d746addc, ee9adb7a45516cfa536ca92253d7ae59d56db9e4, 5.10 |
| Linux | Linux Kernel | 5.9.5 up to, but not including, 5.10; 5.10.1 up to, but not including, 5.10.176; 5.11 up to, but not including, 5.15.104; 5.16 up to, but not including, 6.1.21; 6.2 up to, but not including, 6.2.8; 5.10; 6.3 | 5.10, 5.10.176, 5.15.104, 6.1.21, 6.2.8 |
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: drm/shmem-helper: Remove another errant put in error path drm_gem_shmem_mmap() doesn't own reference in error code path, resulting in the dma-buf shmem GEM object getting prematurely freed leading to a later use-after-free.
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/5cfb617967b05f8f27e862c97db1fabd8485f4db
- git.kernel.org/stable/c/684c7372bbd6447c2e86a2a84e97a1478604d21f
- git.kernel.org/stable/c/77d26c824aa5a7e0681ef1d5b75fe538d746addc
- git.kernel.org/stable/c/dede8c14a37a7ac458f9add56154a074ed78e7cf
- git.kernel.org/stable/c/ee9adb7a45516cfa536ca92253d7ae59d56db9e4
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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