# CVE-2022-48726: RDMA/ucma: Protect mc during concurrent multicast leaves

> A use-after-free vulnerability in the Linux kernel RDMA subsystem allows attackers to cause denial of service or potentially execute code via concurrent multicast operations.

- **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:** 20 Jun 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-48726, GHSA-2pg7-r8hw-8m7v, UBUNTU-CVE-2022-48726

## What is CVE-2022-48726?

CVE-2022-48726 is a high-severity use after free vulnerability in Linux kernel, published on 20 Jun 2024. 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/ucma: Protect mc during concurrent multicast leaves

Partially revert the commit mentioned in the Fixes line to make sure that
allocation and erasing multicast struct are locked.

  BUG: KASAN: use-after-free in ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline]
  BUG: KASAN: use-after-free in ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579
  Read of size 8 at addr ffff88801bb74b00 by task syz-executor.1/25529
  CPU: 0 PID: 25529 Comm: syz-executor.1 Not tainted 5.16.0-rc7-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
   __dump_stack lib/dump_stack.c:88 [inline]
   dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
   print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247
   __kasan_report mm/kasan/report.c:433 [inline]
   kasan_report.cold+0x83/0xdf mm/kasan/report.c:450
   ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline]
   ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579
   ucma_destroy_id+0x1e6/0x280 drivers/infiniband/core/ucma.c:614
   ucma_write+0x25c/0x350 drivers/infiniband/core/ucma.c:1732
   vfs_write+0x28e/0xae0 fs/read_write.c:588
   ksys_write+0x1ee/0x250 fs/read_write.c:643
   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
   do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Currently the xarray search can touch a concurrently freeing mc as the
xa_for_each() is not surrounded by any lock. Rather than hold the lock for
a full scan hold it only for the effected items, which is usually an empty
list.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-48726?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-48726?

Apply the vendor's patch.

## Is CVE-2022-48726 being exploited?

There is no known exploitation of CVE-2022-48726 in the wild and no public exploit code.

## 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-2022-48726 and fix it if it is affected.

What it is: CVE-2022-48726 is a high-severity use after free vulnerability in Linux kernel, published on 20 Jun 2024. 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-2022-48726 in the wild and no public exploit code.

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-2022-48726/ (Markdown: https://insights.sbomify.com/CVE-2022-48726/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-48726
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-48726
- OSV: https://osv.dev/vulnerability/CVE-2022-48726

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-48726/
Summaries are generated and may contain mistakes; the official description above is the record.