# CVE-2026-90065: net/smc: release the internal TCP sock on IPPROTO_SMC socket creation failure

> An unprivileged local attacker can cause a kernel memory leak and denial of service by triggering SMC socket creation failures with a BPF program.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-90065, DEBIAN-CVE-2026-90065, GHSA-6c8w-4wvx-63q5, UBUNTU-CVE-2026-90065

## What is CVE-2026-90065?

CVE-2026-90065 is a memory corruption vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

net/smc: release the internal TCP sock on IPPROTO_SMC socket creation failure

IPPROTO_SMC sockets create an internal TCP sock ("clcsock") from the
proto->init hook. When socket creation fails after proto->init has
run - e.g. a cgroup BPF program attached to BPF_CGROUP_INET_SOCK_CREATE
denies the socket - sk_common_release() only invokes sk_prot->destroy
if it is set, but neither smc_inet_prot nor smc_inet6_prot defines it,
and smc_destruct() returns early unless sk_state is SMC_CLOSED. As a
result, every failing socket(AF_INET, SOCK_STREAM, IPPROTO_SMC) call
leaks one tcp_sock, so an unprivileged task able to attach a deny-all
BPF_CGROUP_INET_SOCK_CREATE program to its own cgroup can grow kernel
memory unboundedly.

Add a .destroy hook to both protos that releases the clcsock via
smc_clcsock_release(). smc_sk_init() hashes the sock into the smc
hashinfo before the clcsock is created, and smc_diag dumps walk that
hash dereferencing smc->clcsock without taking clcsock_release_lock,
while sk_common_release() calls .destroy before .unhash. Unhash the
sock before releasing the clcsock, as __smc_release() does, so a
concurrent dump cannot observe the release; the second unhash in
sk_common_release() is a no-op.

## Which versions are affected by CVE-2026-90065?


## How do I fix CVE-2026-90065?

Apply the vendor's patch.

## Is CVE-2026-90065 being exploited?

There is no known exploitation of CVE-2026-90065 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90065 and fix it if it is affected.

What it is: CVE-2026-90065 is a memory corruption vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-90065 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-2026-90065/ (Markdown: https://insights.sbomify.com/CVE-2026-90065/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90065
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90065
- OSV: https://osv.dev/vulnerability/CVE-2026-90065

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90065/
Summaries are generated and may contain mistakes; the official description above is the record.