CyberSecBulletin
CVE-2026-52908NVD status: Modified

Linux: Improper Authorization

Published Updated By the CyberSecBulletin desk

CVE-2026-52908 is a high-severity improper authorization 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 09dc18894148381d3bfc550083b1236043870dce, eba5df21eda0fe7418efbea2f799f8ea1b8ca94c, 2904e985a2917b5dac65df82733065e78a65fc9d 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 0.12% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 09dc18894148381d3bfc550083b1236043870dce or eba5df21eda0fe7418efbea2f799f8ea1b8ca94c or 2904e985a2917b5dac65df82733065e78a65fc9d or 50334a05a950840b39a1ce3d2a173b4183db9b3e, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.143 or 6.12.94 or 6.18.36 or 7.0.13, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxb40656aa7d559adc1fe689396dc58b92a9a27286 up to, but not including, 09dc18894148381d3bfc550083b1236043870dce; b40656aa7d559adc1fe689396dc58b92a9a27286 up to, but not including, eba5df21eda0fe7418efbea2f799f8ea1b8ca94c; b40656aa7d559adc1fe689396dc58b92a9a27286 up to, but not including, 2904e985a2917b5dac65df82733065e78a65fc9d; b40656aa7d559adc1fe689396dc58b92a9a27286 up to, but not including, 50334a05a950840b39a1ce3d2a173b4183db9b3e; b40656aa7d559adc1fe689396dc58b92a9a27286 up to, but not including, badad6fad60def1b9805559dd81dbab3d97b82aa; 6.209dc18894148381d3bfc550083b1236043870dce, eba5df21eda0fe7418efbea2f799f8ea1b8ca94c, 2904e985a2917b5dac65df82733065e78a65fc9d, 50334a05a950840b39a1ce3d2a173b4183db9b3e, badad6fad60def1b9805559dd81dbab3d97b82aa
LinuxLinux Kernel6.2 up to, but not including, 6.6.143; 6.7 up to, but not including, 6.12.94; 6.13 up to, but not including, 6.18.36; 6.19 up to, but not including, 7.0.13; 7.16.6.143, 6.12.94, 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
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 CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: RDMA: During rereg_mr ensure that REREG_ACCESS is compatible If IB_MR_REREG_ACCESS changes from RO to RW then the umem has to be re-evaluated to ensure it is properly pinned as RW. Since the umem is hidden inside each driver's mr struct add a ib_umem_check_rereg() function that each driver has to call before processing IB_MR_REREG_ACCESS. mlx4 has to retain its duplicate ib_access_writable check because it implements IB_MR_REREG_ACCESS | IB_MR_REREG_TRANS by changing both items in place sequentially while the MR is live, so it will continue to not support this combination.

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.

More Improper Authorization vulnerabilities (CWE-285)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Authorization vulnerabilities

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