# CVE-2026-64319: nvmet-auth: validate reply message payload bounds against transfer length

> A malicious NVMe-oF initiator can trigger out-of-bounds heap reads in the Linux kernel's nvmet-auth module, potentially leaking memory or causing a crash.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-64319, DEBIAN-CVE-2026-64319, GHSA-78p6-7rph-cp36, ROOT-OS-DEBIAN-12-CVE-2026-64319, ROOT-OS-UBUNTU-2204-CVE-2026-64319, UBUNTU-CVE-2026-64319

## What is CVE-2026-64319?

CVE-2026-64319 is a critical memory corruption vulnerability in Linux kernel, published on 25 Jul 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-auth: validate reply message payload bounds against transfer length

nvmet_auth_reply() accesses the variable-length rval[] array using
attacker-controlled hl (hash length) and dhvlen (DH value length) fields
without verifying they fit within the allocated buffer of tl bytes.

A malicious NVMe-oF initiator can craft a DHCHAP_REPLY message with a
small transfer length but large hl/dhvlen values, causing out-of-bounds
heap reads when the target processes the DH public key (rval + 2*hl) or
performs the host response memcmp.

With DH authentication configured, the OOB pointer is passed directly to
sg_init_one() and read by crypto_kpp_compute_shared_secret(), reaching
up to 526 bytes past the buffer. This is exploitable pre-authentication.

Add bounds validation ensuring sizeof(*data) + 2*hl + dhvlen <= tl before
any access to the variable-length fields.

Discovered by Atuin - Automated Vulnerability Discovery Engine.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-64319?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64319?

Apply the vendor's patch.

## Is CVE-2026-64319 being exploited?

There is no known exploitation of CVE-2026-64319 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-2026-64319 and fix it if it is affected.

What it is: CVE-2026-64319 is a critical memory corruption vulnerability in Linux kernel, published on 25 Jul 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-2026-64319 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-2026-64319/ (Markdown: https://insights.sbomify.com/CVE-2026-64319/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64319
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64319
- OSV: https://osv.dev/vulnerability/CVE-2026-64319

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64319/
Summaries are generated and may contain mistakes; the official description above is the record.