# CVE-2024-28757: Denial of service in n/a

> Attackers can cause denial of service via XML Entity Expansion in libexpat when using isolated external parsers.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Mar 2024
- **Updated:** 15 Oct 2026
- **Also known as:** ALPINE-CVE-2024-28757, AZL-35841, AZL-35880, BELL-CVE-2024-28757, CLEANSTART-2026-UG42747, CLSA-2025-1741291038, DEBIAN-CVE-2024-28757, ECHO-a55f-edc3-4bae, GHSA-ch5v-h69f-mxc8, JLSEC-2025-61, RHBA-2024:2518, ROOT-OS-DEBIAN-11-CVE-2024-28757, UBUNTU-CVE-2024-28757, openSUSE-SU-2024:13779-1

## What is CVE-2024-28757?

CVE-2024-28757 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 10 Mar 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libexpat through 2.6.1 allows an XML Entity Expansion attack when there is isolated use of external parsers (created via XML_ExternalEntityParserCreate).

Weakness: CWE-776 (Improper Restriction of Recursive Entity References in DTDs)

## Which versions are affected by CVE-2024-28757?

It affects 14 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `expat-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.5.0-2.el9_4 |
| `expat-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.5.0-2.el9_4 |
| `expat-devel` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.5.0-2.el9_4 |
| `expat` | Red Hat:enterprise_linux:9::baseos | All versions | 0:2.5.0-2.el9_4 |
| `expat-debuginfo` | Red Hat:enterprise_linux:9::baseos | All versions | 0:2.5.0-2.el9_4 |
| `expat-debugsource` | Red Hat:enterprise_linux:9::baseos | All versions | 0:2.5.0-2.el9_4 |
| `expat` | openSUSE:Tumbleweed | All versions | 2.6.2-1.1 |

Products: Fedoraproject Fedora, Libexpat Project Libexpat, Netapp Active Iq Unified Manager, Netapp H300s Firmware, Netapp H410c Firmware, Netapp H410s Firmware, Netapp H500s Firmware, Netapp H610c Firmware, Netapp H610s Firmware, Netapp H700s Firmware, Netapp Oncommand Workflow Automation, Netapp Ontap, Netapp Ontap Tools, Netapp Windows Host Utilities.

## How do I fix CVE-2024-28757?

Upgrade to a fixed version.

## Is CVE-2024-28757 being exploited?

There is no known exploitation of CVE-2024-28757 in the wild and no public exploit code.

Public exploit code:

- https://github.com/RenukaSelvar/expat_CVE-2024-28757 (github_poc): https://github.com/RenukaSelvar/expat_CVE-2024-28757
- https://github.com/saurabh2088/expat_2_1_0_CVE-2024-28757 (github_poc): https://github.com/saurabh2088/expat_2_1_0_CVE-2024-28757

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-28757 and fix it if it is affected.

What it is: CVE-2024-28757 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 10 Mar 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-28757 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2024-28757/ (Markdown: https://insights.sbomify.com/CVE-2024-28757/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-28757
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-28757
- OSV: https://osv.dev/vulnerability/CVE-2024-28757

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-28757/
Summaries are generated and may contain mistakes; the official description above is the record.