Is CVE-2026-64538 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-64538 being exploited in the wild.

How severe is CVE-2026-64538?

Informational severity, with a CVSS score of 6.2, published 27 July 2026.

Which products and versions are affected?

Linux Kernel c0b220cf7d80 to 46c3b8191aad (mainline).

Is there a fix for CVE-2026-64538?

A patch was published on 2026-06-22: Patch merged into mainline kernel Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-64538 attacked?

It is attacked over the network, in an operating system.

Am I affected by CVE-2026-64538?

Check whether you run Linux Kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-64538: Linux Kernel null pointer dereference in fib6_nh_mtu_change

CVE-2026-64538 · Severity: info · CVSS 6.2 · Published 2026-07-27

A vulnerability was identified in the Linux kernel's IPv6 networking component. The issue occurs when the system processes specific network configuration changes, potentially leading to a system crash (kernel oops). This could result in a denial-of-service, impacting the availability of the affected server or device.

Technologies: Linux Kernel. Vendors: Linux.

Quick answers

Is CVE-2026-64538 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-64538 being exploited in the wild.
How severe is CVE-2026-64538?: Informational severity, with a CVSS score of 6.2, published 27 July 2026.
Which products and versions are affected?: Linux Kernel c0b220cf7d80 to 46c3b8191aad (mainline).
Is there a fix for CVE-2026-64538?: A patch was published on 2026-06-22: Patch merged into mainline kernel Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-64538 attacked?: It is attacked over the network, in an operating system.
Am I affected by CVE-2026-64538?: Check whether you run Linux Kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A null pointer dereference exists in the fib6_nh_mtu_change() function within net/ipv6/route.c. The vulnerability is caused by an unguarded re-fetch of the 'idev' pointer via __in6_dev_get(arg->dev). During an interface shutdown (addrconf_ifdown), the dev->ip6_ptr can be cleared while a Router Advertisement (RA)-driven MTU update walk is still in progress. Because nexthop-backed routes can survive the initial flush, the walk may attempt to dereference a NULL idev pointer, resulting in a general protection fault. The fix introduces a NULL check to safely return 0 if the device pointer has been cleared.

Affected products

Linux Linux Kernel c0b220cf7d80 to 46c3b8191aad (mainline)

Timeline

2026-06-18: disclosed: Initial patch authored
2026-06-22: patched: Patch merged into mainline kernel
2026-07-27: advisory: CVE published to NVD

References

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