Linux: Improper Authorization
CVE-2026-53188 is a high-severity improper authorization vulnerability in Linux, with a CVSS 3.1 base score of 8.8 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 96b6e98ff12d50ed5817230c6f1188e1150d225d, aa181287ebdcc53ee0ba5c2f8243e2d541ebc19b, 4a1b1ac2744694a2ecd66a84bdb1445f4ef24bee 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 96b6e98ff12d50ed5817230c6f1188e1150d225d or aa181287ebdcc53ee0ba5c2f8243e2d541ebc19b or 4a1b1ac2744694a2ecd66a84bdb1445f4ef24bee, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.36 or 7.0.13, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 61e51682816d395307f78ae06d640089054c28ab up to, but not including, 96b6e98ff12d50ed5817230c6f1188e1150d225d; 61e51682816d395307f78ae06d640089054c28ab up to, but not including, aa181287ebdcc53ee0ba5c2f8243e2d541ebc19b; 61e51682816d395307f78ae06d640089054c28ab up to, but not including, 4a1b1ac2744694a2ecd66a84bdb1445f4ef24bee; 6.15 | 96b6e98ff12d50ed5817230c6f1188e1150d225d, aa181287ebdcc53ee0ba5c2f8243e2d541ebc19b, 4a1b1ac2744694a2ecd66a84bdb1445f4ef24bee |
| Linux | Linux Kernel | 6.15 up to, but not including, 6.18.36; 6.19 up to, but not including, 7.0.13; 7.1 | 6.18.36, 7.0.13 |
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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:C/C:H/I:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Validate the passed in fops for ib_get_ucaps() Sashiko pointed out it is not safe to rely only on the devt because char/block alias so if the user finds a block device with the same dev_t it can masquerade as a ucap cdev fd. Test the f_ops to only accept authentic cdevs.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authorization
The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
How developers prevent this class of flaw
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Ensure that you perform access control checks related to your business logic. These checks may be different than the access control checks that you apply to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework and the OWASP ESAPI Access Control feature.
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
Recent Improper Authorization vulnerabilities
- 7.6 High severity
- 7.1 High severity
- 7.1 High severity
- 7.8 High severity
- 7.5 High severity
- 7.3 High severity
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