# CVE-2026-80892: erofs: cap LZMA stream pool size

> A malicious EROFS image can cause excessive memory consumption in the Linux kernel, leading to 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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** AZL-99555, BELL-CVE-2026-80892, DEBIAN-CVE-2026-80892, GHSA-6hp7-9qfx-w4m8, UBUNTU-CVE-2026-80892

## What is CVE-2026-80892?

CVE-2026-80892 is a denial of service vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

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

erofs: cap LZMA stream pool size

fs/erofs/decompressor_lzma.c sizes the module-global MicroLZMA stream
pool from num_possible_cpus() when the lzma_streams module parameter is
unset, then z_erofs_load_lzma_config() preallocates one image-supplied
dictionary per stream, accepting dictionaries up to 8 MiB.  On high-CPU
systems, a small EROFS image can pin hundreds of MiB of vmalloc-backed
decoder state until the erofs module is unloaded.

Impact: An EROFS image mounted by the system can pin up to 8 MiB of
vmalloc memory per LZMA stream, either as intended or unexpectedly.

Bound the default stream count by a new
CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS option, default 16, so the
worst-case default preallocation is 128 MiB if the number of CPUs is no
less than 16 while preserving the existing per-image dictionary limit.
An explicit lzma_streams module parameter is still honoured as-is, so
administrators who deliberately size the pool are not affected.

## Which versions are affected by CVE-2026-80892?


## How do I fix CVE-2026-80892?

Apply the vendor's patch.

## Is CVE-2026-80892 being exploited?

There is no known exploitation of CVE-2026-80892 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80892 and fix it if it is affected.

What it is: CVE-2026-80892 is a denial of service vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-80892 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-2026-80892/ (Markdown: https://insights.sbomify.com/CVE-2026-80892/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80892
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80892
- OSV: https://osv.dev/vulnerability/CVE-2026-80892

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80892/
Summaries are generated and may contain mistakes; the official description above is the record.