CVE-2026-63955 Details
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().
A vulnerability in the Linux kernel's virtual memory management can cause the system to improperly trigger a BUG() error when it should not. This issue arises in the __get_vm_area_node() function, which mistakenly interprets the context as being in_interrupt() when bottom halves are disabled. The problem can occur in bridge code that manipulates the hash lock, disabling bottom halves and then calling rhashtable_lookup_insert_fast(). This sequence leads to the allocation of memory via vmalloc(), which in turn calls __get_vm_area_node() and triggers the BUG() error. The vulnerability affects the Linux kernel stable tree.
The vulnerability has been addressed by modifying the __get_vm_area_node() function to check for in_nmi() or in_hardirq() instead of in_interrupt(). Users should apply the latest patches available in the Linux kernel stable tree to mitigate this issue.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/04aa71da5f35aacdc9ae9cb5150947daa624f641 | kernel.org | |
| https://git.kernel.org/stable/c/ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce | kernel.org |
Weakness Enumeration
No weakness enumeration is available for this CVE.
Affected Products
No affected product data is available for this CVE.
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 20, 2026 | CVE Modified | kernel.org |
| Jul 19, 2026 | New CVE Received | kernel.org |