# CVE-2022-49393: misc: fastrpc: fix list iterator in fastrpc_req_mem_unmap_impl

> A logic error in the Linux kernel's fastrpc driver causes a kernel crash when unmapping memory, leading to 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:** 26 Feb 2025
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-49393, GHSA-jh22-4f6v-h4ph, ROOT-OS-UBUNTU-2204-CVE-2022-49393, UBUNTU-CVE-2022-49393

## What is CVE-2022-49393?

CVE-2022-49393 is a high-severity vulnerability in Linux kernel, published on 26 Feb 2025. 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:

misc: fastrpc: fix list iterator in fastrpc_req_mem_unmap_impl

This is another instance of incorrect use of list iterator and
checking it for NULL.

The list iterator value 'map' will *always* be set and non-NULL
by list_for_each_entry(), so it is incorrect to assume that the
iterator value will be NULL if the list is empty (in this case, the
check 'if (!map) {' will always be false and never exit as expected).

To fix the bug, use a new variable 'iter' as the list iterator,
while use the original variable 'map' as a dedicated pointer to
point to the found element.

Without this patch, Kernel crashes with below trace:

Unable to handle kernel access to user memory outside uaccess routines
 at virtual address 0000ffff7fb03750
...
Call trace:
 fastrpc_map_create+0x70/0x290 [fastrpc]
 fastrpc_req_mem_map+0xf0/0x2dc [fastrpc]
 fastrpc_device_ioctl+0x138/0xc60 [fastrpc]
 __arm64_sys_ioctl+0xa8/0xec
 invoke_syscall+0x48/0x114
 el0_svc_common.constprop.0+0xd4/0xfc
 do_el0_svc+0x28/0x90
 el0_svc+0x3c/0x130
 el0t_64_sync_handler+0xa4/0x130
 el0t_64_sync+0x18c/0x190
Code: 14000016 f94000a5 eb05029f 54000260 (b94018a6)
---[ end trace 0000000000000000 ]---

Weakness: CWE-670 (Always-Incorrect Control Flow Implementation)

## Which versions are affected by CVE-2022-49393?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49393?

Apply the vendor's patch.

## Is CVE-2022-49393 being exploited?

There is no known exploitation of CVE-2022-49393 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-2022-49393 and fix it if it is affected.

What it is: CVE-2022-49393 is a high-severity vulnerability in Linux kernel, published on 26 Feb 2025. 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-2022-49393 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-2022-49393/ (Markdown: https://insights.sbomify.com/CVE-2022-49393/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49393
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49393
- OSV: https://osv.dev/vulnerability/CVE-2022-49393

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49393/
Summaries are generated and may contain mistakes; the official description above is the record.