CVE-2026-89763
Description
In the Linux kernel, the following vulnerability has been resolved: KEYS: trusted: Fix TPM teardown ordering trusted_tpm_exit() drops the TPM chip reference and frees the digest array before unregistering the trusted key type. key_type_lookup() holds key_types_sem for reading until the key operation finishes, while unregister_key_type() takes it for writing. It therefore provides the synchronization point that must precede backend teardown. The current order permits this interleaving: CPU 0 CPU 1 trusted_tpm_exit() key_type_lookup("trusted") put_device(&chip->dev) trusted_tpm_seal() kfree(digests) pcrlock() unregister_key_type() tpm_pcr_extend(..., digests) CPU 1 can consequently dereference the freed digest array. The chip can also be released before callbacks stop using it. KASAN reported: BUG: KASAN: slab-use-after-free in tpm_pcr_extend+0x1f0/0x200 Read of size 2 at addr ffff88810872d000 by task poc/89 Call Trace: tpm_pcr_extend+0x1f0/0x200 pcrlock+0x42/0x70 [trusted] trusted_tpm_seal+0x1b6/0x570 [trusted] trusted_instantiate+0x293/0x340 [trusted] __key_instantiate_and_link+0xb2/0x2b0 __key_create_or_update+0x61e/0xb50 __do_sys_add_key+0x1b8/0x310 Allocated by task 88: __kmalloc_noprof+0x1a7/0x490 do_one_initcall+0xa1/0x390 do_init_module+0x2df/0x840 Freed by task 90: kfree+0x131/0x3c0 trusted_tpm_exit+0x59/0xa0 [trusted] __do_sys_delete_module+0x346/0x510 Move unregister_key_type() before releasing either resource. This stops new lookups and waits for in-flight key operations to finish before the backend state is destroyed.
How to fix
- Linux Linuxb254cdadbcb6bdd0daf7391d63b3b97b2bec1ad9, c96518231608bbf9568f539aadb20a8e366b54c7, 6564808189c9a1e682ee7b5e70f5f1c73c89c3a4, 81dfc6c665547a4e41721b6716f894f263a5e03f, 3d67b4acbfc7af331d887a8efc04bef6573b8a7a, 753c978f2400f9783eb524842a975d3ac950d511, 2f7541afbc57fe9d26769a22c31d8ce8790c9a19, 5e2d672280d97d83de43031d93761b12dadd7b8a or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 ≤ v < b254cdadbcb6bdd0daf7391d63b3b97b2bec1ad9, 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 ≤ v < c96518231608bbf9568f539aadb20a8e366b54c7, 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 ≤ v < 6564808189c9a1e682ee7b5e70f5f1c73c89c3a4, 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 ≤ v < 81dfc6c665547a4e41721b6716f894f263a5e03f, 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 ≤ v < 3d67b4acbfc7af331d887a8efc04bef6573b8a7a, 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 ≤ v < 753c978f2400f9783eb524842a975d3ac950d511, 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 ≤ v < 2f7541afbc57fe9d26769a22c31d8ce8790c9a19, 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 ≤ v < 5e2d672280d97d83de43031d93761b12dadd7b8a, 5.1 | b254cdadbcb6bdd0daf7391d63b3b97b2bec1ad9, c96518231608bbf9568f539aadb20a8e366b54c7, 6564808189c9a1e682ee7b5e70f5f1c73c89c3a4, 81dfc6c665547a4e41721b6716f894f263a5e03f, 3d67b4acbfc7af331d887a8efc04bef6573b8a7a, 753c978f2400f9783eb524842a975d3ac950d511, 2f7541afbc57fe9d26769a22c31d8ce8790c9a19, 5e2d672280d97d83de43031d93761b12dadd7b8a |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.