SEPTEMBER 8, 2026
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Case File

CVE-2026-63955

HIGH · CVSS 7.5 EPSS 0.47%

Source: NVD + CISA KEV + EPSS · Published 2026-07-19 · Last synced 2026-08-18

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's memory management subsystem, specifically within the `__get_vm_area_node()` function, which improperly triggers a BUG() when called in a context where bottom halves (BH) are disabled. This can lead to system instability or crashes when certain bridge operations are performed, particularly during network packet processing. Organizations using Linux systems, especially those relying on networking features, should prioritize patching this vulnerability to mitigate potential disruptions in service.

CVE
CVE-2026-63955
Severity
HIGH
CVSS
7.5
EPSS
0.47%
Linux

Original NVD 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().