How severe is CVE-2026-89763?

CVE-2026-89763 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-89763?

CVE-2026-89763 affects the following packages: Kernel (Linux). Ecosystems affected: Linux.

How do I fix CVE-2026-89763?

Update Kernel to 6.18.50 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-89763 is resolved across your whole dependency graph.

How do I detect CVE-2026-89763 in my Linux dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-89763 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-89763?

O3 pinpoints whether CVE-2026-89763 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-89763 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-89763 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2026-89763 published, and has it been updated?

CVE-2026-89763 was published on September 11, 2026 and was last updated on September 14, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐧

🐧 Linux

Not in CISA KEV

HIGH severity

CVE-2026-89763

HIGH

CVE-2026-89763 is a high-severity (CVSS 7.8) vulnerability in Kernel. O3 Security confirms whether CVE-2026-89763 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

KEYS: trusted: Fix TPM teardown ordering

Published

Sep 11, 2026

Updated

Sep 14, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 14, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐧Kernel

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐧Linux	`Kernel`	≥ 5.1.0&&< 6.18.50	6.18.50

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Kernel to 6.18.50 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-89763 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-89763 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-89763. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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")

O3 Security · Impact-Aware SCA

Is CVE-2026-89763 in your dependencies?

O3 detects CVE-2026-89763 across Linux dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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