Linux: Use After Free
CVE-2023-53386 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 e87da6a0ac6e631454e7da53a76aa9fe44aaa5dd, 942d8cefb022f384d5424f8b90c7878f3f93726f, 94617b736c25091b60e514e2e7aeafcbbee6b700 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 0.15% 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 e87da6a0ac6e631454e7da53a76aa9fe44aaa5dd or 942d8cefb022f384d5424f8b90c7878f3f93726f or 94617b736c25091b60e514e2e7aeafcbbee6b700 or da19f35868dfbecfff4f81166c054d2656cb1be4, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.195 or 5.15.132 or 6.1.53 or 6.4.16, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | d7d41682efc25d58b5bd8b80e85e3c9ce586635c up to, but not including, e87da6a0ac6e631454e7da53a76aa9fe44aaa5dd; d7d41682efc25d58b5bd8b80e85e3c9ce586635c up to, but not including, 942d8cefb022f384d5424f8b90c7878f3f93726f; d7d41682efc25d58b5bd8b80e85e3c9ce586635c up to, but not including, 94617b736c25091b60e514e2e7aeafcbbee6b700; d7d41682efc25d58b5bd8b80e85e3c9ce586635c up to, but not including, da19f35868dfbecfff4f81166c054d2656cb1be4; d7d41682efc25d58b5bd8b80e85e3c9ce586635c up to, but not including, 35cc42f04bc49f0656f6840cb7451b3df6049649; d7d41682efc25d58b5bd8b80e85e3c9ce586635c up to, but not including, 3673952cf0c6cf81b06c66a0b788abeeb02ff3ae; 5.7 | e87da6a0ac6e631454e7da53a76aa9fe44aaa5dd, 942d8cefb022f384d5424f8b90c7878f3f93726f, 94617b736c25091b60e514e2e7aeafcbbee6b700, da19f35868dfbecfff4f81166c054d2656cb1be4, 35cc42f04bc49f0656f6840cb7451b3df6049649, 3673952cf0c6cf81b06c66a0b788abeeb02ff3ae |
| Linux | Linux Kernel | 5.7 up to, but not including, 5.10.195; 5.11 up to, but not including, 5.15.132; 5.16 up to, but not including, 6.1.53; 6.2 up to, but not including, 6.4.16; 6.5 up to, but not including, 6.5.3 | 5.10.195, 5.15.132, 6.1.53, 6.4.16, 6.5.3 |
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 | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Fix potential use-after-free when clear keys Similar to commit c5d2b6fa26b5 ("Bluetooth: Fix use-after-free in hci_remove_ltk/hci_remove_irk"). We can not access k after kfree_rcu() call.
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/35cc42f04bc49f0656f6840cb7451b3df6049649
- git.kernel.org/stable/c/3673952cf0c6cf81b06c66a0b788abeeb02ff3ae
- git.kernel.org/stable/c/942d8cefb022f384d5424f8b90c7878f3f93726f
- git.kernel.org/stable/c/94617b736c25091b60e514e2e7aeafcbbee6b700
- git.kernel.org/stable/c/da19f35868dfbecfff4f81166c054d2656cb1be4
- git.kernel.org/stable/c/e87da6a0ac6e631454e7da53a76aa9fe44aaa5dd
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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