# CVE-2026-97477: RDMA/counter: Fix num_counters leak on bind_qp failure in alloc_and_bind()

> A resource leak in the Linux kernel RDMA counter module allows attackers to permanently block port mode switching, causing denial of service.

- **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:** 24 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-103781, BELL-CVE-2026-97477, DEBIAN-CVE-2026-97477, GHSA-8gp2-fhh5-vxhw, UBUNTU-CVE-2026-97477

## What is CVE-2026-97477?

CVE-2026-97477 is a denial of service vulnerability in Linux, published on 24 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:

RDMA/counter: Fix num_counters leak on bind_qp failure in alloc_and_bind()

When __rdma_counter_bind_qp() fails in alloc_and_bind(), the error path
jumps to err_mode which frees the counter without decrementing
port_counter->num_counters. The only place that decrements is
rdma_counter_free(), which is unreachable since the counter was never
successfully bound.

This leak accumulates across repeated failures, permanently preventing
the port from switching to AUTO mode (-EBUSY in __counter_set_mode())
and blocking the MANUAL→NONE auto-revert in rdma_counter_free(). When
the mode was NONE before the call, the MANUAL mode set by
__counter_set_mode() also leaks since the revert logic is never
reached.

Add an err_bind label between the num_counters increment and the
existing err_mode label. It decrements num_counters and mirrors the
MANUAL→NONE revert from rdma_counter_free(), ensuring the port state
is fully restored on bind failure.

## Which versions are affected by CVE-2026-97477?


## How do I fix CVE-2026-97477?

Apply the vendor's patch.

## Is CVE-2026-97477 being exploited?

There is no known exploitation of CVE-2026-97477 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97477 and fix it if it is affected.

What it is: CVE-2026-97477 is a denial of service vulnerability in Linux, published on 24 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-2026-97477 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-2026-97477/ (Markdown: https://insights.sbomify.com/CVE-2026-97477/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97477
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97477
- OSV: https://osv.dev/vulnerability/CVE-2026-97477

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97477/
Summaries are generated and may contain mistakes; the official description above is the record.