CVE-2026-64192 Linux vulnerability
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.
Browse Linux security risksQuick answer
Linux should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- < c76b8abce575e0c6e4096957220b4515ed847d89
- < a6f0643e4f63cfaa0d5d4a69de4f132eac4b8fe4
- 5.10
Fixed versions
- 7.1.4
- 7.2-rc2
How to fix it
CVE-2026-64192 affects Linux and involves denial of service. A remote or untrusted peer may consume excessive resources or crash the affected service. Prioritize deployments that process untrusted input, expose the affected feature, or hold sensitive data. Upgrade Linux to 7.1.4, 7.2-rc2 or a later vendor-supported fixed release.
- Inventory every deployment, device, package, plugin, container, build, and environment that uses Linux.
- Compare the installed version with the recorded affected range: < c76b8abce575e0c6e4096957220b4515ed847d89, < a6f0643e4f63cfaa0d5d4a69de4f132eac4b8fe4, 5.10.
- Upgrade Linux to 7.1.4, 7.2-rc2 or a later vendor-supported fixed release.
- Until patched, limit untrusted files and peers, apply resource limits, and isolate the affected parser or service.
- Review configuration, roles, tokens, network paths, and exposed endpoints connected to Linux; remove access that is not required.
- Review application, system, proxy, and audit logs for requests and behavior linked to the affected feature and CVE.
- If exploitation is suspected, isolate affected assets, preserve evidence, rotate exposed credentials or keys, restore trusted data, and rebuild compromised systems before returning them to service.
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Verify the fix
- Confirm every affected asset now runs the fixed vendor-supported release or has the documented mitigation for CVE-2026-64192 in place.
- Use a safe regression test to confirm the affected denial of service path no longer produces the vulnerable behavior.
- Confirm temporary access controls, endpoint restrictions, network blocks, and least-privilege settings remain effective after the update.
- Review post-remediation logs and rerun Fixnx plus the relevant package, dependency, firmware, browser, or product-specific security check.
- Document affected assets, versions, changes, validation evidence, reviewed logs, and any credential rotation, cleanup, or replacement completed.
Related categories
Related security risks
More published guidance from the same primary category.
Trusted references
FAQ
What is affected by CVE-2026-64192?
Linux versions listed as affected should be reviewed: < c76b8abce575e0c6e4096957220b4515ed847d89, < a6f0643e4f63cfaa0d5d4a69de4f132eac4b8fe4, 5.10.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.