GHSA-J4RG-4W46-639C
Vulnerability from github – Published: 2026-11-02 18:32 – Updated: 2026-11-03 21:31In the Linux kernel, the following vulnerability has been resolved:
keys: Protect the read method check against type removal
keyctl_read_key() checks key->type->read without holding key->sem. A reference keeps the key alive, but does not pin the module containing its type. A surviving RxRPC key can therefore be read while AF_RXRPC is being unloaded:
KEYCTL_READ task Module unload and key GC ---------------- ------------------------ lookup_user_key() permission / possession checks load key->type af_rxrpc_exit() unregister_key_type() GC: down_write(key->sem) GC: retype to key_type_dead GC: up_write(key->sem) unregister_key_type() returns free_module() read saved type's read member
The final access can read freed module storage. The read invocation in __keyctl_read_key() is already protected by key->sem, but the earlier method check is outside that critical section.
Move the method check into __keyctl_read_key(), after key_validate() and under its existing read hold on key->sem. The check and invocation then use the same protected type for length queries and every read retry. The GC cannot retype the key until the semaphore is released, and type unregistration waits for that GC pass before the module can be freed.
Return -EOPNOTSUPP when validation succeeds and the type has no read method. A temporary buffer may now be allocated before this result; allocation and copying to userspace remain outside the semaphore.
{
"affected": [],
"aliases": [
"CVE-2026-99222"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-11-02T16:17:46Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nkeys: Protect the read method check against type removal\n\nkeyctl_read_key() checks key-\u003etype-\u003eread without holding key-\u003esem.\nA reference keeps the key alive, but does not pin the module containing\nits type. A surviving RxRPC key can therefore be read while AF_RXRPC\nis being unloaded:\n\n KEYCTL_READ task Module unload and key GC\n ---------------- ------------------------\n lookup_user_key()\n permission / possession checks\n load key-\u003etype\n af_rxrpc_exit()\n unregister_key_type()\n GC: down_write(key-\u003esem)\n GC: retype to key_type_dead\n GC: up_write(key-\u003esem)\n unregister_key_type() returns\n free_module()\n read saved type\u0027s read member\n\nThe final access can read freed module storage. The read invocation in\n__keyctl_read_key() is already protected by key-\u003esem, but the earlier\nmethod check is outside that critical section.\n\nMove the method check into __keyctl_read_key(), after key_validate() and\nunder its existing read hold on key-\u003esem. The check and invocation then\nuse the same protected type for length queries and every read retry.\nThe GC cannot retype the key until the semaphore is released, and type\nunregistration waits for that GC pass before the module can be freed.\n\nReturn -EOPNOTSUPP when validation succeeds and the type has no read\nmethod. A temporary buffer may now be allocated before this result;\nallocation and copying to userspace remain outside the semaphore.",
"id": "GHSA-j4rg-4w46-639c",
"modified": "2026-11-03T21:31:59Z",
"published": "2026-11-02T18:32:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99222"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1486caee47b4909f52835a957c3293e970113e44"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3edc064069d07e7d37359fcb4d03d3bab15ee3ab"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6a36e2a1a017c51f8a8ad2a094566bad97c46a9b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/925c84e3cc21caf09de92d9bcafab0147790debf"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cf1af7df80e38bf58bd74c2cccce32fcbd1a596a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e2a2deda08d91644f5e30c17d267b1cdc5f124b2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e5f830ae6611cddbfc504c43f14155f60b63206a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ff11cfed85cbfdd7fe1185ebd18d2c7a8353ad8d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ff44f1b303aa76a818d898e85c56ed4852c031e2"
}
],
"schema_version": "1.4.0",
"severity": []
}
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