# CVE-2026-90107: net/smc: free pending qentry in smc_llc_flow_stop() before memset

> A memory leak in the Linux kernel SMC protocol allows remote attackers to exhaust kernel memory via crafted network messages, causing denial of service.

- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102797, BELL-CVE-2026-90107, DEBIAN-CVE-2026-90107, GHSA-mw8r-cvfc-f297, UBUNTU-CVE-2026-90107

## What is CVE-2026-90107?

CVE-2026-90107 is a memory corruption vulnerability in Linux, published on 17 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/smc: free pending qentry in smc_llc_flow_stop() before memset

smc_llc_flow_stop() resets a flow struct with a blind memset:

	spin_lock_bh(&lgr->llc_flow_lock);
	memset(flow, 0, sizeof(*flow));
	flow->type = SMC_LLC_FLOW_NONE;
	spin_unlock_bh(&lgr->llc_flow_lock);

If flow->qentry is non-NULL at this point the pointer is overwritten without the
allocation being freed, leaking one kmalloc object.

A late-arriving duplicate CONFIRM_LINK or ADD_LINK_CONT message can set
flow->qentry after the legitimate message has been consumed by the waiter via
smc_llc_flow_qentry_clr() (which NULLs the pointer but leaves flow->type
non-zero) but before the flow completes and smc_llc_flow_stop() runs.  In that
window the duplicate is stashed into flow->qentry, and then lost when
smc_llc_flow_stop() zeros the struct.

Call smc_llc_flow_qentry_del() inside the lock before the memset.
smc_llc_flow_qentry_del() already checks flow->qentry before freeing, so the
normal case where no entry is pending is a no-op.

## Which versions are affected by CVE-2026-90107?


## How do I fix CVE-2026-90107?

Apply the vendor's patch.

## Is CVE-2026-90107 being exploited?

There is no known exploitation of CVE-2026-90107 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90107 and fix it if it is affected.

What it is: CVE-2026-90107 is a memory corruption vulnerability in Linux, published on 17 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-2026-90107 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-2026-90107/ (Markdown: https://insights.sbomify.com/CVE-2026-90107/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90107
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90107
- OSV: https://osv.dev/vulnerability/CVE-2026-90107

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90107/
Summaries are generated and may contain mistakes; the official description above is the record.