# CVE-2026-43502: net/rds: handle zerocopy send cleanup before the message is queued

> A memory leak in the Linux kernel RDS module occurs during zerocopy send failures, potentially leading to resource exhaustion and denial of service.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 21 May 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-87075, BELL-CVE-2026-43502, DEBIAN-CVE-2026-43502, GHSA-mhq7-fqmq-29pq, ROOT-OS-DEBIAN-11-CVE-2026-43502, ROOT-OS-DEBIAN-12-CVE-2026-43502, ROOT-OS-UBUNTU-2204-CVE-2026-43502, ROOT-OS-UBUNTU-2404-CVE-2026-43502, UBUNTU-CVE-2026-43502

## What is CVE-2026-43502?

CVE-2026-43502 is a high-severity memory corruption vulnerability in Linux kernel, published on 21 May 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/rds: handle zerocopy send cleanup before the message is queued

A zerocopy send can fail after user pages have been pinned but before
the message is attached to the sending socket.

The purge path currently infers zerocopy state from rm->m_rs, so an
unqueued message can be cleaned up as if it owned normal payload pages.
However, zerocopy ownership is really determined by the presence of
op_mmp_znotifier, regardless of whether the message has reached the
socket queue.

Capture op_mmp_znotifier up front in rds_message_purge() and use it as
the cleanup discriminator. If the message is already associated with a
socket, keep the existing completion path. Otherwise, drop the pinned
page accounting directly and release the notifier before putting the
payload pages.

This keeps early send failure cleanup consistent with the zerocopy
lifetime rules without changing the normal queued completion path.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-43502?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43502?

Apply the vendor's patch.

## Is CVE-2026-43502 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43502 exists.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43502 and fix it if it is affected.

What it is: CVE-2026-43502 is a high-severity memory corruption vulnerability in Linux kernel, published on 21 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43502 exists.

Affected product: Linux kernel. 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-2026-43502/ (Markdown: https://insights.sbomify.com/CVE-2026-43502/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43502
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43502
- OSV: https://osv.dev/vulnerability/CVE-2026-43502

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43502/
Summaries are generated and may contain mistakes; the official description above is the record.