CVE-2026-72052
Description
A flaw was found in the Linux kernel's ip6_gre and ip6erspan tunnel drivers. The changelink functions in these drivers do not adequately verify administrative capabilities (CAP_NET_ADMIN) across different network namespaces. This allows a local attacker, who has CAP_NET_ADMIN in one network namespace but not in the tunnel's network namespace, to modify the tunnel's configuration. This could lead to unauthorized changes to network tunnel settings.
Mitigation
If IPv6 GRE or IP-ERSpan tunnels are not in use, their respective kernel modules (`ip6_gre` and `ip6erspan`) can be blacklisted to prevent exploitation. Create a file such as `/etc/modprobe.d/disable-ip6gre.conf` with the following content:
install ip6_gre /bin/true
install ip6erspan /bin/true
After creating the file, regenerate the initramfs and reboot the system for the changes to take effect. This mitigation may impact network functionality if these tunnel types are actively used.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.8 | N/A | 8.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Changed |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
A user can access restricted functionality and/or sensitive information that may include administrative functionality and user accounts.
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