# CVE-2026-89576: dm-era: fix shadowed superblock leak on take-snap failure

> A resource leak in the Linux kernel dm-era driver allows local attackers to exhaust metadata space, 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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100892, BELL-CVE-2026-89576, DEBIAN-CVE-2026-89576, GHSA-f7fr-q69f-62x9, UBUNTU-CVE-2026-89576

## What is CVE-2026-89576?

CVE-2026-89576 is a denial of service vulnerability in Linux, published on 11 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-era: fix shadowed superblock leak on take-snap failure

metadata_take_snap() bumps the live superblock refcount and then
dm_tm_shadow_block() allocates a new block for the metadata snapshot.
If the subsequent dm_sm_inc_block() of writeset_tree_root or
era_array_root fails, the function only unlocks the clone and
returns.  The newly allocated shadow block is never returned to the
metadata space map, so each failed take-snap permanently leaks one
metadata block.

Free the clone with dm_sm_dec_block() on those error paths, matching
the final step of metadata_drop_snap().

## Which versions are affected by CVE-2026-89576?


## How do I fix CVE-2026-89576?

Apply the vendor's patch.

## Is CVE-2026-89576 being exploited?

There is no known exploitation of CVE-2026-89576 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89576 and fix it if it is affected.

What it is: CVE-2026-89576 is a denial of service vulnerability in Linux, published on 11 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-2026-89576 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-2026-89576/ (Markdown: https://insights.sbomify.com/CVE-2026-89576/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89576
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89576
- OSV: https://osv.dev/vulnerability/CVE-2026-89576

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89576/
Summaries are generated and may contain mistakes; the official description above is the record.