# CVE-2026-72330: net/tls: Consume empty data records in tls_sw_read_sock()

> A remote attacker can cause a denial of service in the Linux kernel TLS implementation by sending zero-length records that block subsequent data processing.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-72330, DEBIAN-CVE-2026-72330, GHSA-744x-88r4-xj59, UBUNTU-CVE-2026-72330

## What is CVE-2026-72330?

CVE-2026-72330 is a high-severity 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:

net/tls: Consume empty data records in tls_sw_read_sock()

A peer may send a zero-length TLS application_data record; TLS 1.3
explicitly permits these as a traffic-analysis countermeasure (RFC
8446, Section 5.1). After decryption such a record has full_len ==
0. tls_sw_read_sock() hands it to the read_actor, which has no
payload to consume and returns zero. The loop treats a zero return
as backpressure (used <= 0), requeues the skb at the head of
rx_list, and stops. rx_list is serviced head-first on the next
call, so the empty record is dequeued, fails the same way, and is
requeued again; every later record on the connection is blocked
behind it.

tls_sw_recvmsg() does not stall on this: a zero-length data record
copies nothing and falls through to consume_skb(). Mirror that in
the read_sock() path by recognizing an empty data record before
the actor runs, consuming it, and continuing.

## Which versions are affected by CVE-2026-72330?


## How do I fix CVE-2026-72330?

Apply the vendor's patch.

## Is CVE-2026-72330 being exploited?

There is no known exploitation of CVE-2026-72330 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72330 and fix it if it is affected.

What it is: CVE-2026-72330 is a high-severity 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-2026-72330 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-2026-72330/ (Markdown: https://insights.sbomify.com/CVE-2026-72330/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72330
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72330
- OSV: https://osv.dev/vulnerability/CVE-2026-72330

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72330/
Summaries are generated and may contain mistakes; the official description above is the record.