Linux: Use After Free
CVE-2023-53305 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 e76bab1b7afa580cd76362540fc37551ada4359b, 1a40c56e8bff3e424724d78a9a6b3272dd8a371d, fe49aa73cca6608714477b74bfc6874b9db979df 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 0.23% 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 e76bab1b7afa580cd76362540fc37551ada4359b or 1a40c56e8bff3e424724d78a9a6b3272dd8a371d or fe49aa73cca6608714477b74bfc6874b9db979df or 2958cf9f805b9f0bdc4a761bf6ea281eb8d44f8e, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.14.324 or 4.19.293 or 5.4.255 or 5.10.192, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 71fb419724fadab4efdf98210aa3fe053bd81d29 up to, but not including, e76bab1b7afa580cd76362540fc37551ada4359b; 71fb419724fadab4efdf98210aa3fe053bd81d29 up to, but not including, 1a40c56e8bff3e424724d78a9a6b3272dd8a371d; 71fb419724fadab4efdf98210aa3fe053bd81d29 up to, but not including, fe49aa73cca6608714477b74bfc6874b9db979df; 71fb419724fadab4efdf98210aa3fe053bd81d29 up to, but not including, 2958cf9f805b9f0bdc4a761bf6ea281eb8d44f8e; 71fb419724fadab4efdf98210aa3fe053bd81d29 up to, but not including, 548a6b64b3c0688f01119a6fcccceb41f8c984e4; 71fb419724fadab4efdf98210aa3fe053bd81d29 up to, but not including, 149daab45922ab1ac7f0cbeacab7251a46bf5e63; 71fb419724fadab4efdf98210aa3fe053bd81d29 up to, but not including, 255be68150291440657b2cdb09420b69441af3d8; 71fb419724fadab4efdf98210aa3fe053bd81d29 up to, but not including, f752a0b334bb95fe9b42ecb511e0864e2768046f; and 1 more ranges | e76bab1b7afa580cd76362540fc37551ada4359b, 1a40c56e8bff3e424724d78a9a6b3272dd8a371d, fe49aa73cca6608714477b74bfc6874b9db979df, 2958cf9f805b9f0bdc4a761bf6ea281eb8d44f8e, 548a6b64b3c0688f01119a6fcccceb41f8c984e4, 149daab45922ab1ac7f0cbeacab7251a46bf5e63 |
| Linux | Linux Kernel | before 4.14.324; 4.15 up to, but not including, 4.19.293; 4.20 up to, but not including, 5.4.255; 5.5 up to, but not including, 5.10.192; 5.11 up to, but not including, 5.15.128; 5.16 up to, but not including, 6.1.47; 6.2 up to, but not including, 6.4.12 | 4.14.324, 4.19.293, 5.4.255, 5.10.192, 5.15.128, 6.1.47 |
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 | 8.8 | High | CNA |
| 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: L2CAP: Fix use-after-free Fix potential use-after-free in l2cap_le_command_rej.
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/149daab45922ab1ac7f0cbeacab7251a46bf5e63
- git.kernel.org/stable/c/1a40c56e8bff3e424724d78a9a6b3272dd8a371d
- git.kernel.org/stable/c/255be68150291440657b2cdb09420b69441af3d8
- git.kernel.org/stable/c/2958cf9f805b9f0bdc4a761bf6ea281eb8d44f8e
- git.kernel.org/stable/c/548a6b64b3c0688f01119a6fcccceb41f8c984e4
- git.kernel.org/stable/c/e76bab1b7afa580cd76362540fc37551ada4359b
- git.kernel.org/stable/c/f752a0b334bb95fe9b42ecb511e0864e2768046f
- git.kernel.org/stable/c/fe49aa73cca6608714477b74bfc6874b9db979df
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
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