Linux Kernel BPF inode_storage_map_alloc missing initialization

Summaryinfo

A vulnerability marked as problematic has been reported in Linux Kernel. Impacted is the function inode_storage_map_alloc of the component BPF. This manipulation causes missing initialization. This vulnerability is handled as CVE-2026-64192. It is possible to launch the attack on the local host. There is not any exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel (the affected version is unknown). It has been declared as problematic. Affected by this vulnerability is the function inode_storage_map_alloc of the component BPF. The manipulation with an unknown input leads to a missing initialization vulnerability. The CWE definition for the vulnerability is CWE-456. The product does not initialize critical variables, which causes the execution environment to use unexpected values. As an impact it is known to affect integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject BPF_MAP_TYPE_INODE_STORAGE creation if BPF LSM is uninitialized When CONFIG_BPF_LSM=y is set, BPF inode storage maps (BPF_MAP_TYPE_INODE_STORAGE) are compiled into the kernel. However, if the BPF LSM is not explicitly enabled at boot time (e.g. omitted from the "lsm=" boot parameter), lsm_prepare() is never executed for the BPF LSM. Consequently, the BPF inode security blob offset (bpf_lsm_blob_sizes.lbs_inode) is never initialized and remains at its default compiled size of 8 bytes instead of being updated to a valid offset past the reserved struct rcu_head (typically 16 bytes or more). When a privileged user creates and updates a BPF_MAP_TYPE_INODE_STORAGE map, bpf_inode() evaluates inode->i_security + 8. This erroneously aliases the struct rcu_head.func callback pointer at the beginning of the inode->i_security blob. During subsequent map element cleanup or inode destruction, writing NULL to owner_storage clears the queued RCU callback pointer. When rcu_do_batch() later executes the queued callback, it attempts an instruction fetch at address 0x0, triggering an immediate kernel panic. Fix this by introducing a global bpf_lsm_initialized boolean flag marked with __ro_after_init. Set this flag to true inside bpf_lsm_init() when the LSM framework successfully registers the BPF LSM. Gate map allocation in inode_storage_map_alloc() on this flag, returning -EOPNOTSUPP if the BPF LSM is in turn uninitialized. This fail-fast approach prevents userspace from allocating inode storage maps when the supporting BPF LSM infrastructure is absent, avoiding zombie map states.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-64192 since 07/19/2026. The exploitation appears to be easy. Attacking locally is a requirement. The exploitation needs additional levels of successful authentication. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/20/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

License

• open-source

Website

• Vendor: https://www.kernel.org/

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