# CVE-2026-89602: erofs: skip sufficiently large global buffers when resizing

> A logic error in the Linux kernel EROFS filesystem causes a buffer overflow during resize retries, leading to a kernel crash and denial of service.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-89602, DEBIAN-CVE-2026-89602, GHSA-jv24-3qj8-gmg3, UBUNTU-CVE-2026-89602

## What is CVE-2026-89602?

CVE-2026-89602 is a high-severity vulnerability in Linux, published on 11 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: skip sufficiently large global buffers when resizing

z_erofs_gbuf_nrpages is advanced only after every global buffer has been
grown. If a resize fails after some buffers were enlarged, a retry
revisits those enlarged buffers.

Retrying the same size then returns -ENOMEM because alloc_pages_bulk()
has no pages to add and the unchanged return value is treated as a
failure. Retrying an intermediate size allocates a temporary pointer
array smaller than gbuf->nrpages and copies more existing pointers than
the array can hold.

Skip buffers that already satisfy the request. Once all remaining
buffers have caught up, advancing z_erofs_gbuf_nrpages again describes
the guaranteed minimum size across the pool.

## Which versions are affected by CVE-2026-89602?


## How do I fix CVE-2026-89602?

Apply the vendor's patch.

## Is CVE-2026-89602 being exploited?

There is no known exploitation of CVE-2026-89602 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89602 and fix it if it is affected.

What it is: CVE-2026-89602 is a high-severity vulnerability in Linux, published on 11 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-2026-89602 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-2026-89602/ (Markdown: https://insights.sbomify.com/CVE-2026-89602/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89602
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89602
- OSV: https://osv.dev/vulnerability/CVE-2026-89602

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89602/
Summaries are generated and may contain mistakes; the official description above is the record.