CyberSecBulletin
CVE-2026-72055NVD status: Received

Linux: Missing Authorization

Published Updated By the CyberSecBulletin desk

CVE-2026-72055 is a high-severity missing 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 f5254e7766b4ac02b66b2ccef896cd278503cb11, ef897249dc957089e6f7f11ceea699e093ad51bd, f6e8b52a2cb3bbd72ddc2d44e474b907b9dcf5ba 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.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to f5254e7766b4ac02b66b2ccef896cd278503cb11 or ef897249dc957089e6f7f11ceea699e093ad51bd or f6e8b52a2cb3bbd72ddc2d44e474b907b9dcf5ba or c64b9ae7eb97e81d54b792910a3aeafd92566c79, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux61220ab349485d911083d0b7990ccd3db6c63297 up to, but not including, f5254e7766b4ac02b66b2ccef896cd278503cb11; 61220ab349485d911083d0b7990ccd3db6c63297 up to, but not including, ef897249dc957089e6f7f11ceea699e093ad51bd; 61220ab349485d911083d0b7990ccd3db6c63297 up to, but not including, f6e8b52a2cb3bbd72ddc2d44e474b907b9dcf5ba; 61220ab349485d911083d0b7990ccd3db6c63297 up to, but not including, c64b9ae7eb97e81d54b792910a3aeafd92566c79; 61220ab349485d911083d0b7990ccd3db6c63297 up to, but not including, b2b61c540571b3cc2f461e2a579ba2cc8c2a52cf; 61220ab349485d911083d0b7990ccd3db6c63297 up to, but not including, 0b2f9c908f930ec4be17d389723f9a202d6a883c; 61220ab349485d911083d0b7990ccd3db6c63297 up to, but not including, f97e93ebf2f9b8ef3b87f7a9371255e84d151587; 61220ab349485d911083d0b7990ccd3db6c63297 up to, but not including, e2ac3b242c37dff323a964962e43854f4b1a2b79; and 1 more rangesf5254e7766b4ac02b66b2ccef896cd278503cb11, ef897249dc957089e6f7f11ceea699e093ad51bd, f6e8b52a2cb3bbd72ddc2d44e474b907b9dcf5ba, c64b9ae7eb97e81d54b792910a3aeafd92566c79, b2b61c540571b3cc2f461e2a579ba2cc8c2a52cf, 0b2f9c908f930ec4be17d389723f9a202d6a883c

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: net: ip6_vti: require CAP_NET_ADMIN in the device netns for changelink vti6_changelink() operates on at most two netns, dev_net(dev) and the tunnel link netns t->net. They differ once the device is created in or moved to a netns other than the one the request runs in. The rtnl changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a caller privileged there but not in t->net can rewrite a tunnel that lives in t->net. Gate vti6_changelink() on rtnl_dev_link_net_capable() at its top, before any attribute is parsed.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Missing Authorization

The product does not perform 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 access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied 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 Missing Authorization vulnerabilities (CWE-862)

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 Missing Authorization vulnerabilities

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