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CVE-2026-63955

7.5 · HIGH

In the Linux kernel, the following vulnerability has been resolved: mm/vmalloc: do not trigger BUG() on BH disabled context __get_vm_area_node() currently triggers a BUG() if in_interrupt() retur…

Published Jul 19, 2026EPSS 0.49%

Overview

CVE-2026-63955 is a high-severity vulnerability. It was published on July 19, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

mm/vmalloc: do not trigger BUG() on BH disabled context

__get_vm_area_node() currently triggers a BUG() if in_interrupt() returns

true. However, in_interrupt() also reports true when BH are disabled.

The bridge code can call rhashtable_lookup_insert_fast() with bottom

halves disabled:

__vlan_add()

-> br_fdb_add_local()

spin_lock_bh(&br->hash_lock); <-- Disable BH

-> fdb_add_local()

-> fdb_create()

-> rhashtable_lookup_insert_fast()

-> kvmalloc()

-> vmalloc()

-> __get_vm_area_node()

-> BUG_ON(in_interrupt())

spin_unlock_bh(&br->hash_lock)

this triggers the BUG() despite the caller not being in NMI or

hard IRQ context.

Replace the in_interrupt() check with in_nmi() || in_hardirq().

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/04aa71da5f35aacdc9ae9cb5150947daa624f641Refgit.kernel.org/stable/c/ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce

How CyberStrike helps

Frequently asked questions

What is CVE-2026-63955?

CVE-2026-63955 is a high-severity vulnerability. It was published on July 19, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-63955?

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-63955?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-63955?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-63955 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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