# CVE-2026-80904: net/tls: Fail tls_sw_splice_read() after a failed async decrypt

> An attacker can bypass TLS authentication checks by exploiting a missing error check in the Linux kernel's TLS splice read function, allowing delivery of unauthenticated data.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** AZL-99525, BELL-CVE-2026-80904, DEBIAN-CVE-2026-80904, GHSA-vp2x-h945-mvcw, UBUNTU-CVE-2026-80904

## What is CVE-2026-80904?

CVE-2026-80904 is a vulnerability in Linux, published on 4 Sep 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: Fail tls_sw_splice_read() after a failed async decrypt

When an async decrypt fails, tls_decrypt_done() records the error in
ctx->async_wait.err and calls tls_err_abort(), which stores it in
sk_err. tls_sw_recvmsg() and tls_sw_read_sock() each read
async_wait.err once they hold the reader lock and fail the call: a
record that did not authenticate breaks the connection.

tls_sw_splice_read() has no such check, and sk_err does not stand in
for one. tls_rx_rec_wait() tests sk_err only inside the loop it
skips whenever a record is already parsed, and the first reader to
reach sock_error() clears it, while async_wait.err persists. A
splice therefore keeps delivering records on a connection that
recvmsg() and read_sock() refuse to read.

Read async_wait.err in tls_sw_splice_read() as the other two readers
do.

## Which versions are affected by CVE-2026-80904?


## How do I fix CVE-2026-80904?

Apply the vendor's patch.

## Is CVE-2026-80904 being exploited?

There is no known exploitation of CVE-2026-80904 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80904 and fix it if it is affected.

What it is: CVE-2026-80904 is a vulnerability in Linux, published on 4 Sep 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-2026-80904 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-2026-80904/ (Markdown: https://insights.sbomify.com/CVE-2026-80904/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80904
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80904
- OSV: https://osv.dev/vulnerability/CVE-2026-80904

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80904/
Summaries are generated and may contain mistakes; the official description above is the record.