# CVE-2026-45961: gfs2: fix memory leaks in gfs2_fill_super error path

> Memory leaks in the GFS2 filesystem error path can lead to resource exhaustion and denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 May 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-88755, BELL-CVE-2026-45961, DEBIAN-CVE-2026-45961, GHSA-848w-4wg8-36v4, ROOT-OS-DEBIAN-11-CVE-2026-45961, ROOT-OS-DEBIAN-12-CVE-2026-45961, ROOT-OS-DEBIAN-13-CVE-2026-45961, ROOT-OS-UBUNTU-2204-CVE-2026-45961, ROOT-OS-UBUNTU-2404-CVE-2026-45961, UBUNTU-CVE-2026-45961

## What is CVE-2026-45961?

CVE-2026-45961 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 May 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:

gfs2: fix memory leaks in gfs2_fill_super error path

Fix two memory leaks in the gfs2_fill_super() error handling path when
transitioning a filesystem to read-write mode fails.

First leak: kthread objects (thread_struct, task_struct, etc.)
When gfs2_freeze_lock_shared() fails after init_threads() succeeds, the
created kernel threads (logd and quotad) are never destroyed. This
occurs because the fail_per_node label doesn't call
gfs2_destroy_threads().

Second leak: quota bitmap buffer (8192 bytes)
When gfs2_make_fs_rw() fails after gfs2_quota_init() succeeds but
before other operations complete, the allocated quota bitmap is never
freed.

The fix moves thread cleanup to the fail_per_node label to handle all
error paths uniformly. gfs2_destroy_threads() is safe to call
unconditionally as it checks for NULL pointers. Quota cleanup is added
in gfs2_make_fs_rw() to properly handle the withdrawal case where
quota initialization succeeds but the filesystem is then withdrawn.

Thread leak backtrace (gfs2_freeze_lock_shared failure):
  unreferenced object 0xffff88801d7bca80 (size 4480):
    copy_process+0x3a1/0x4670 kernel/fork.c:2422
    kernel_clone+0xf3/0x6e0 kernel/fork.c:2779
    kthread_create_on_node+0x100/0x150 kernel/kthread.c:478
    init_threads+0xab/0x350 fs/gfs2/ops_fstype.c:611
    gfs2_fill_super+0xe5c/0x1240 fs/gfs2/ops_fstype.c:1265

Quota leak backtrace (gfs2_make_fs_rw failure):
  unreferenced object 0xffff88812de7c000 (size 8192):
    gfs2_quota_init+0xe5/0x820 fs/gfs2/quota.c:1409
    gfs2_make_fs_rw+0x7a/0xe0 fs/gfs2/super.c:149
    gfs2_fill_super+0xfbb/0x1240 fs/gfs2/ops_fstype.c:1275

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-45961?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-45961?

Apply the vendor's patch.

## Is CVE-2026-45961 being exploited?

There is no known exploitation of CVE-2026-45961 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45961 and fix it if it is affected.

What it is: CVE-2026-45961 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 May 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-2026-45961 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-45961/ (Markdown: https://insights.sbomify.com/CVE-2026-45961/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45961
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45961
- OSV: https://osv.dev/vulnerability/CVE-2026-45961

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45961/
Summaries are generated and may contain mistakes; the official description above is the record.