Linux Kernel: Use After Free
CVE-2022-42896 is a high-severity use after free vulnerability in Linux Kernel from Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected Linux Kernel versions: 3.0.0 through 711f8c3fb3db61897080468586b970c87c61d9e4. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 2.46% chance of exploitation within 30 days, higher than 85% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to V1.1 or a later version.
- Read the advisory on kernel.dance for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux Kernel | 3.0.0 through 711f8c3fb3db61897080468586b970c87c61d9e4 | Not stated |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | before V1.1 | V1.1 |
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
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.0 | High | CNA (google.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
There are use-after-free vulnerabilities in the Linux kernel's net/bluetooth/l2cap_core.c's l2cap_connect and l2cap_le_connect_req functions which may allow code execution and leaking kernel memory (respectively) remotely via Bluetooth. A remote attacker could execute code leaking kernel memory via Bluetooth if within proximity of the victim. We recommend upgrading past commit https://www.google.com/url https://github.com/torvalds/linux/commit/711f8c3fb3db61897080468586b970c87c61d9e4 https://www.google.com/url
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
- github.com/torvalds/linux/commit/711f8c3fb3db61897080468586b970c87c61d9e4Third Party Advisory
Other references
Other vulnerabilities in Linux Kernel
- 9.8 Critical severity
- 7.0 High severity
- 7.8 High severity
- 7.1 High severity
- 7.0 High severity
- 7.8 High severity
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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