# CVE-2026-99062: vsock/virtio: account only unread bytes in read_skb()


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** BELL-CVE-2026-99062, DEBIAN-CVE-2026-99062, GHSA-q643-38mv-p69j, UBUNTU-CVE-2026-99062

## What is CVE-2026-99062?

CVE-2026-99062 is a vulnerability in Linux, published on 23 Oct 2026. 

### Official description

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

vsock/virtio: account only unread bytes in read_skb()

After a partial stream receive, rx_bytes tracks the unread suffix while
buf_used and peer credit still cover the whole packet.
virtio_transport_read_skb() dequeues that packet but passes pkt_len for
both counters, underflowing rx_bytes.

On a connected CID_LOCAL stream with an SK_SKB verdict, a 40-byte read
from a 100-byte packet made SIOCINQ report -40, an empty recv return
ELOOP, and poll report the empty socket readable.  After verdict detach,
receiving 40 bytes wrapped the counter to zero and hid those queued bytes
until one more byte arrived.  The fixed run kept the counter balanced
and exposed all queued data immediately.

This was found during an LLM-assisted manual source audit of VSOCK
receive accounting while re-evaluating virtio_transport_read_skb() after
CVE-2024-50169.

Subtract only skb->len minus the VSOCK offset from rx_bytes.  Retain the
full packet length for buf_used and peer credit.

## Which versions are affected by CVE-2026-99062?


## How do I fix CVE-2026-99062?

Upgrade to a fixed version.

## Is CVE-2026-99062 being exploited?

There is no known exploitation of CVE-2026-99062 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99062 and fix it if it is affected.

What it is: CVE-2026-99062 is a vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99062 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-2026-99062/ (Markdown: https://insights.sbomify.com/CVE-2026-99062/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99062
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99062
- OSV: https://osv.dev/vulnerability/CVE-2026-99062

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99062/
Summaries are generated and may contain mistakes; the official description above is the record.