# CVE-2026-90320: ocfs2: validate external xattr entries when reading metadata

> A use-after-free vulnerability in the Linux kernel's OCFS2 filesystem allows attackers to execute code or cause a denial of service via corrupted metadata.

- **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:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-102764, BELL-CVE-2026-90320, DEBIAN-CVE-2026-90320, GHSA-hcpc-9v72-qf3v, UBUNTU-CVE-2026-90320

## What is CVE-2026-90320?

CVE-2026-90320 is a high-severity use after free vulnerability in Linux, published on 17 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:

ocfs2: validate external xattr entries when reading metadata

ocfs2_validate_xattr_block() checks the xattr block header before the
block reaches higher-level xattr users, but it does not verify that a
non-indexed block's xh_count and entry offsets fit inside the block. 
Indexed buckets likewise reach list/get consumers after ECC without an
entry-bounds check.

Use the flat xattr entry validator for non-indexed external xattr blocks,
and use a bucket-specific validator for indexed buckets at metadata read
time.  The bucket validator keeps the entry array bounded by the first
bucket block while checking name/value offsets against the bucket block
they target.

Reject corrupted external xattr metadata before listxattr() or getxattr()
can walk out-of-range entry arrays or name/value offsets.

Validation reproduced this kernel report:
BUG: KASAN: use-after-free in ocfs2_xattr_list_entries+0xd7/0x190
Read of size 1 at addr ffff88810a654007 by task ocfs2_xattr_lis/630
Call Trace:
  dump_stack_lvl+0x66/0xa0
  print_report+0xce/0x630
  kasan_report+0xe0/0x110
  ocfs2_xattr_list_entries+0xd7/0x190
  ocfs2_listxattr+0x3f6/0x610
  listxattr+0x90/0xe0
  path_listxattrat+0xed/0x220
  do_syscall_64+0x115/0x6a0
  entry_SYSCALL_64_after_hwframe+0x77/0x7f

## Which versions are affected by CVE-2026-90320?


## How do I fix CVE-2026-90320?

Apply the vendor's patch.

## Is CVE-2026-90320 being exploited?

There is no known exploitation of CVE-2026-90320 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90320 and fix it if it is affected.

What it is: CVE-2026-90320 is a high-severity use after free vulnerability in Linux, published on 17 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-2026-90320 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-2026-90320/ (Markdown: https://insights.sbomify.com/CVE-2026-90320/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90320
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90320
- OSV: https://osv.dev/vulnerability/CVE-2026-90320

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90320/
Summaries are generated and may contain mistakes; the official description above is the record.