# CVE-2026-72339: qede: fix off-by-one in BD ring consumption on build_skb failure

> An off-by-one error in the qede network driver can corrupt memory and cause system crashes or potential code execution under memory pressure.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-72339, DEBIAN-CVE-2026-72339, GHSA-447g-7f2j-g4vp, UBUNTU-CVE-2026-72339

## What is CVE-2026-72339?

CVE-2026-72339 is a critical memory corruption 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:

qede: fix off-by-one in BD ring consumption on build_skb failure

qede_rx_build_skb() and qede_tpa_rx_build_skb() do not check for a
NULL return from qede_build_skb(). When it returns NULL under memory
pressure, the functions still consume a BD from the ring before
returning NULL. The callers then recycle additional BDs, resulting in
one extra BD being consumed (off-by-one). This desynchronizes the BD
ring, which can corrupt DMA page reference counts and lead to SLUB
freelist corruption.

Commit 4e910dbe3650 ("qede: confirm skb is allocated before using")
added a NULL check inside qede_build_skb() to prevent a NULL pointer
dereference, but did not address the missing NULL checks in the
callers, making this off-by-one reachable.

Fix this by adding NULL checks for the return value of
qede_build_skb() in both qede_rx_build_skb() and
qede_tpa_rx_build_skb(), returning NULL immediately before any BD ring
manipulation.

## Which versions are affected by CVE-2026-72339?


## How do I fix CVE-2026-72339?

Apply the vendor's patch.

## Is CVE-2026-72339 being exploited?

There is no known exploitation of CVE-2026-72339 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72339 and fix it if it is affected.

What it is: CVE-2026-72339 is a critical memory corruption 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-2026-72339 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-2026-72339/ (Markdown: https://insights.sbomify.com/CVE-2026-72339/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72339
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72339
- OSV: https://osv.dev/vulnerability/CVE-2026-72339

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72339/
Summaries are generated and may contain mistakes; the official description above is the record.