# CVE-2026-90333: dm-integrity: replace forgeable discard filler with a keyed sector marker

> An attacker with raw write access can bypass integrity checks by forging discard markers, requiring local access and specific configuration.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-102681, BELL-CVE-2026-90333, DEBIAN-CVE-2026-90333, GHSA-62c9-4g59-6rj6, UBUNTU-CVE-2026-90333

## What is CVE-2026-90333?

CVE-2026-90333 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:

dm-integrity: replace forgeable discard filler with a keyed sector marker

The discard-block check in dm_integrity_rw_tag() treats a stored tag
of all 0xf6 bytes (DISCARD_FILLER) as proof a block was discarded and
skips HMAC verification. allow_discards is only accepted in
dm-integrity's standalone mode. An attacker with raw write access to
the backing device, but without the integrity key, can stamp any block
with an all-0xf6 tag and have it served as authentic.

Add a new "allow_discards_keyed" target argument that marks discarded
blocks with a keyed checksum of (salt || sector) instead, computed by
integrity_discard_checksum().

## Which versions are affected by CVE-2026-90333?


## How do I fix CVE-2026-90333?

Apply the vendor's patch.

## Is CVE-2026-90333 being exploited?

There is no known exploitation of CVE-2026-90333 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90333 and fix it if it is affected.

What it is: CVE-2026-90333 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-2026-90333 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-2026-90333/ (Markdown: https://insights.sbomify.com/CVE-2026-90333/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90333
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90333
- OSV: https://osv.dev/vulnerability/CVE-2026-90333

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90333/
Summaries are generated and may contain mistakes; the official description above is the record.