# CVE-2026-90070: tpm: st33zp24: Return zero on status read failure

> A flaw in the Linux kernel TPM driver allows uninitialized stack data to be interpreted as status flags, potentially leaking memory or causing denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102855, BELL-CVE-2026-90070, DEBIAN-CVE-2026-90070, GHSA-q7v7-xw33-v766, UBUNTU-CVE-2026-90070

## What is CVE-2026-90070?

CVE-2026-90070 is a vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

tpm: st33zp24: Return zero on status read failure

st33zp24_status() ignores the result of the transport read and returns
data even when no byte was received. The I2C transport, for example,
skips i2c_master_recv() when the register-select write is short or fails,
leaving data uninitialized. The resulting stack value can be interpreted
as TPM_STS flags and let status checks complete spuriously.

The status callback cannot propagate a transport error. Return zero
unless recv() reports exactly one byte. With no status bits set, callers
retry or take their existing timeout or error path instead of acting on
an invalid status value.

This issue was found by a static analysis checker and confirmed by manual
source review.

## Which versions are affected by CVE-2026-90070?


## How do I fix CVE-2026-90070?

Apply the vendor's patch.

## Is CVE-2026-90070 being exploited?

There is no known exploitation of CVE-2026-90070 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90070 and fix it if it is affected.

What it is: CVE-2026-90070 is a vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-90070 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-90070/ (Markdown: https://insights.sbomify.com/CVE-2026-90070/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90070
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90070
- OSV: https://osv.dev/vulnerability/CVE-2026-90070

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90070/
Summaries are generated and may contain mistakes; the official description above is the record.