kernel: Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2023-32254 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in kernel, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 2.91% chance of exploitation within 30 days, higher than 87% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux Kernel to 5.15.145 or 6.1.28 or 6.2.15 or 6.3.2, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Kernel | kernel | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Fedora | Fedora | Not specified in the record | Not stated |
| Linux | Linux Kernel | 5.15 up to, but not including, 5.15.145; 5.16 up to, but not including, 6.1.28; 6.2 up to, but not including, 6.2.15; 6.3 up to, but not including, 6.3.2 | 5.15.145, 6.1.28, 6.2.15, 6.3.2 |
| NetApp | Hci Management Node | Not specified in the record | Not stated |
| NetApp | H300s | Not specified in the record | Not stated |
| NetApp | H410s | Not specified in the record | Not stated |
| NetApp | H500s | Not specified in the record | Not stated |
| NetApp | H700s | Not specified in the record | Not stated |
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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- 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:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | CNA (redhat.com) |
| CVSS 3.1 | 8.1 | High | NVD |
Official description
A flaw was found in the Linux kernel's ksmbd, a high-performance in-kernel SMB server. The specific flaw exists within the processing of SMB2_TREE_DISCONNECT commands. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to execute code in the context of the kernel.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Concurrent Execution using Shared Resource with Improper Synchronization
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
How developers prevent this class of flaw
- In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
- Use thread-safe capabilities such as the data access abstraction in Spring.
- Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- bugzilla.redhat.com/show_bug.cgi?id=2191658Issue Tracking, Third Party Advisory
- zerodayinitiative.com/advisories/ZDI-23-702/Third Party Advisory, VDB Entry
Third-party and government advisories
- access.redhat.com/security/cve/CVE-2023-32254Third Party Advisory
- security.netapp.com/advisory/ntap-20230824-0004/Third Party Advisory
Other vulnerabilities in kernel
- 7.5 High severity
- 7.8 High severity
- 8.1 High severity
- 7.1 High severity
- 8.1 High severity
- 8.1 High severity
Recent Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities
- 8.1 High severity
- 7.0 High severity
- 7.0 High severity
- 7.8 High severity
- 7.5 High severity
- 9.8 Critical severity
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