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VulnerabilityPublished Updated

CVE-2026-89763: Linux kernel · KEYS: trusted: Fix TPM teardown ordering

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in 753c978f2400f9783eb524842a975d3ac950d511 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in 753c978f2400f9783eb524842a975d3ac950d511, 81dfc6c665547a4e41721b6716f894f263a5e03f, 5e2d672280d97d83de43031d93761b12dadd7b8a +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400, < 753c978f2400f9783eb524842a975d3ac950d511
Fixed in
  • 753c978f2400f9783eb524842a975d3ac950d511
LinuxLinuxAffected
  • ≥ 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400, < 81dfc6c665547a4e41721b6716f894f263a5e03f
Fixed in
  • 81dfc6c665547a4e41721b6716f894f263a5e03f
LinuxLinuxAffected
  • ≥ 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400, < 5e2d672280d97d83de43031d93761b12dadd7b8a
Fixed in
  • 5e2d672280d97d83de43031d93761b12dadd7b8a
LinuxLinuxAffected
  • ≥ 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400, < 3d67b4acbfc7af331d887a8efc04bef6573b8a7a
Fixed in
  • 3d67b4acbfc7af331d887a8efc04bef6573b8a7a
LinuxLinuxAffected
  • ≥ 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400, < 2f7541afbc57fe9d26769a22c31d8ce8790c9a19
Fixed in
  • 2f7541afbc57fe9d26769a22c31d8ce8790c9a19
LinuxLinuxAffected
  • =5.1
Fixed in–

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.

References

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