# CVE-2026-74309: vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler

> Incorrect IRQ-to-ring mapping in the Octeon EP vDPA driver can cause incorrect ring indexing, potentially leading to system instability or denial of service.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-74309, DEBIAN-CVE-2026-74309, GHSA-mxhm-35m8-cqc9, UBUNTU-CVE-2026-74309

## What is CVE-2026-74309?

CVE-2026-74309 is a critical 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:

vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler

Look up the IRQ index in oct_hw->irqs instead of assuming
irq - irqs[0]. This supports non-contiguous IRQ numbers and
avoids incorrect ring indexing when irqs[0] is not the base.

## Which versions are affected by CVE-2026-74309?


## How do I fix CVE-2026-74309?

Apply the vendor's patch.

## Is CVE-2026-74309 being exploited?

There is no known exploitation of CVE-2026-74309 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74309 and fix it if it is affected.

What it is: CVE-2026-74309 is a critical 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-2026-74309 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-2026-74309/ (Markdown: https://insights.sbomify.com/CVE-2026-74309/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74309
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74309
- OSV: https://osv.dev/vulnerability/CVE-2026-74309

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74309/
Summaries are generated and may contain mistakes; the official description above is the record.