# CVE-2026-74386: nvmet-tcp: fix page fragment cache leak in error path

> A memory leak in the Linux kernel's nvmet-tcp module allows remote attackers to cause denial of service by repeatedly opening and closing connections.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-96468, BELL-CVE-2026-74386, DEBIAN-CVE-2026-74386, GHSA-3685-2pvg-g2mr, UBUNTU-CVE-2026-74386

## What is CVE-2026-74386?

CVE-2026-74386 is a denial of service vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

nvmet-tcp: fix page fragment cache leak in error path

In nvmet_tcp_alloc_queue(), when a connection is closed during the
allocation process (e.g., nvmet_tcp_set_queue_sock() returns -ENOTCONN),
the error handling jumps to out_destroy_sq and then to out_ida_remove
without draining the page fragment cache.

Although nvmet_tcp_free_cmd() is called in some error paths to release
individual page fragments, the underlying page cache reference held by
queue->pf_cache is never released. The first allocation using pf_cache
is the call to nvmet_tcp_alloc_cmd() for queue->connect, which happens
after ida_alloc() returns successfully. This results in a page leak each
time a connection fails during allocation, which could lead to memory
exhaustion over time if connections are repeatedly opened and closed.

Fix this by calling page_frag_cache_drain() before freeing the queue
structure in the out_ida_remove label.

## Which versions are affected by CVE-2026-74386?


## How do I fix CVE-2026-74386?

Apply the vendor's patch.

## Is CVE-2026-74386 being exploited?

There is no known exploitation of CVE-2026-74386 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74386 and fix it if it is affected.

What it is: CVE-2026-74386 is a denial of service vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74386 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-2026-74386/ (Markdown: https://insights.sbomify.com/CVE-2026-74386/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74386
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74386
- OSV: https://osv.dev/vulnerability/CVE-2026-74386

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74386/
Summaries are generated and may contain mistakes; the official description above is the record.