GHSA-3HVR-PHFH-X26G
Vulnerability from github – Published: 2026-07-20 18:32 – Updated: 2026-07-20 18:32In 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.
{
"affected": [],
"aliases": [
"CVE-2026-64192"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-20T17:18:22Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject BPF_MAP_TYPE_INODE_STORAGE creation if BPF LSM is uninitialized\n\nWhen CONFIG_BPF_LSM=y is set, BPF inode storage maps\n(BPF_MAP_TYPE_INODE_STORAGE) are compiled into the kernel. However,\nif the BPF LSM is not explicitly enabled at boot time (e.g. omitted\nfrom the \"lsm=\" boot parameter), lsm_prepare() is never executed for\nthe BPF LSM.\n\nConsequently, the BPF inode security blob offset\n(bpf_lsm_blob_sizes.lbs_inode) is never initialized and remains at\nits default compiled size of 8 bytes instead of being updated to a\nvalid offset past the reserved struct rcu_head (typically 16 bytes\nor more).\n\nWhen a privileged user creates and updates a BPF_MAP_TYPE_INODE_STORAGE\nmap, bpf_inode() evaluates inode-\u003ei_security + 8. This erroneously\naliases the struct rcu_head.func callback pointer at the beginning\nof the inode-\u003ei_security blob. During subsequent map element cleanup\nor inode destruction, writing NULL to owner_storage clears the queued\nRCU callback pointer. When rcu_do_batch() later executes the queued\ncallback, it attempts an instruction fetch at address 0x0, triggering\nan immediate kernel panic.\n\nFix this by introducing a global bpf_lsm_initialized boolean flag\nmarked with __ro_after_init. Set this flag to true inside bpf_lsm_init()\nwhen the LSM framework successfully registers the BPF LSM. Gate map\nallocation in inode_storage_map_alloc() on this flag, returning\n-EOPNOTSUPP if the BPF LSM is in turn uninitialized.\n\nThis fail-fast approach prevents userspace from allocating inode\nstorage maps when the supporting BPF LSM infrastructure is absent,\navoiding zombie map states.",
"id": "GHSA-3hvr-phfh-x26g",
"modified": "2026-07-20T18:32:33Z",
"published": "2026-07-20T18:32:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64192"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a6f0643e4f63cfaa0d5d4a69de4f132eac4b8fe4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c76b8abce575e0c6e4096957220b4515ed847d89"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.