Linux: Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2022-49001 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in Linux, with a CVSS 3.1 base score of 7.0 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 ac00301adb19df54f2eae1efc4bad7447c0156ce, 879fabc5a95401d9bce357e4b1d24ae4a360a81f, 7e1864332fbc1b993659eab7974da9fe8bf8c128 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 0.19% 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 ac00301adb19df54f2eae1efc4bad7447c0156ce or 879fabc5a95401d9bce357e4b1d24ae4a360a81f or 7e1864332fbc1b993659eab7974da9fe8bf8c128, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.82 or 6.0.12, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 31da94c25aea835ceac00575a9fd206c5a833fed up to, but not including, ac00301adb19df54f2eae1efc4bad7447c0156ce; 31da94c25aea835ceac00575a9fd206c5a833fed up to, but not including, 879fabc5a95401d9bce357e4b1d24ae4a360a81f; 31da94c25aea835ceac00575a9fd206c5a833fed up to, but not including, 7e1864332fbc1b993659eab7974da9fe8bf8c128; 5.14 | ac00301adb19df54f2eae1efc4bad7447c0156ce, 879fabc5a95401d9bce357e4b1d24ae4a360a81f, 7e1864332fbc1b993659eab7974da9fe8bf8c128 |
| Linux | Linux Kernel | 5.14 up to, but not including, 5.15.82; 5.16 up to, but not including, 6.0.12; 6.1 | 5.15.82, 6.0.12 |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.0 | High | CNA |
| CVSS 3.1 | 7.0 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: riscv: fix race when vmap stack overflow Currently, when detecting vmap stack overflow, riscv firstly switches to the so called shadow stack, then use this shadow stack to call the get_overflow_stack() to get the overflow stack. However, there's a race here if two or more harts use the same shadow stack at the same time. To solve this race, we introduce spin_shadow_stack atomic var, which will be swap between its own address and 0 in atomic way, when the var is set, it means the shadow_stack is being used; when the var is cleared, it means the shadow_stack isn't being used. [Palmer: Add AQ to the swap, and also some comments.]
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities
- 7.0 High severity
- 7.0 High severity
- 8.1 High severity
- 8.2 High severity
- 7.9 High severity
- 7.5 High severity
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