# CVE-2025-40928: Integer overflow in JSON::XS

> An integer buffer overflow in the JSON::XS Perl library allows attackers to cause a denial of service via crafted JSON input.

- **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:** 8 Sep 2025
- **Updated:** 4 Nov 2025
- **Also known as:** ALSA-2025:17119, ALSA-2025:17162, ALSA-2025:17163, AZL-67076, AZL-67079, DEBIAN-CVE-2025-40928, DLA-4317-1, DSA-5999-1, GHSA-v8qr-gpx9-78rm, MGASA-2025-0283, OESA-2025-2365, OESA-2025-2366, OESA-2025-2367, OESA-2025-2447, OESA-2025-2448, OESA-2025-2449, RHSA-2025:17119, RHSA-2025:17162, RHSA-2025:17163, RHSA-2025:17430, RLSA-2025:17119, RLSA-2025:17162, RLSA-2025:17163, UBUNTU-CVE-2025-40928, USN-7750-1, openSUSE-SU-2025:15535-1

## What is CVE-2025-40928?

CVE-2025-40928 is a high-severity vulnerability in MLEHMANN JSON::XS, published on 8 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

JSON::XS before version 4.04 for Perl has an integer buffer overflow causing a segfault when parsing crafted JSON, enabling denial-of-service attacks or other unspecified impact

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2025-40928?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `perl-JSON-XS` | AlmaLinux:10 | All versions | 1:4.04-1.el10_0 |
| `perl-JSON-XS` | AlmaLinux:8 | All versions | 1:3.04-4.el8_10 |
| `perl-JSON-XS` | AlmaLinux:9 | All versions | 1:4.04-1.el9_6 |
| `perl-JSON-XS` | Red Hat:enterprise_linux:10.0 | All versions | 1:4.04-1.el10_0 |
| `perl-JSON-XS-debuginfo` | Red Hat:enterprise_linux:10.0 | All versions | 1:4.04-1.el10_0 |
| `perl-JSON-XS-debugsource` | Red Hat:enterprise_linux:10.0 | All versions | 1:4.04-1.el10_0 |
| `perl-JSON-XS` | Red Hat:enterprise_linux:8::crb | All versions | 1:3.04-4.el8_10 |
| `perl-JSON-XS-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:3.04-4.el8_10 |
| `perl-JSON-XS-debugsource` | Red Hat:enterprise_linux:8::crb | All versions | 1:3.04-4.el8_10 |
| `perl-JSON-XS` | Red Hat:enterprise_linux:9::crb | All versions | 1:4.04-1.el9_6 |
| `perl-JSON-XS-debuginfo` | Red Hat:enterprise_linux:9::crb | All versions | 1:4.04-1.el9_6 |
| `perl-JSON-XS-debugsource` | Red Hat:enterprise_linux:9::crb | All versions | 1:4.04-1.el9_6 |
| `perl-JSON-XS` | Red Hat:rhel_eus:9.4::crb | All versions | 1:4.03-5.el9_4.1 |
| `perl-JSON-XS-debuginfo` | Red Hat:rhel_eus:9.4::crb | All versions | 1:4.03-5.el9_4.1 |
| `perl-JSON-XS-debugsource` | Red Hat:rhel_eus:9.4::crb | All versions | 1:4.03-5.el9_4.1 |
| `perl-JSON-XS` | Rocky Linux:10 | All versions | 1:4.04-1.el10_0 |
| `perl-JSON-XS` | Rocky Linux:8 | All versions | 1:3.04-4.el8_10 |
| `perl-JSON-XS` | Rocky Linux:9 | All versions | 1:4.04-1.el9_6 |
| `perl-JSON-XS` | openSUSE:Tumbleweed | All versions | 4.40.0-1.1 |

## How do I fix CVE-2025-40928?

Upgrade to a fixed version.

## Is CVE-2025-40928 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-40928 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40928 and fix it if it is affected.

What it is: CVE-2025-40928 is a high-severity vulnerability in MLEHMANN JSON::XS, published on 8 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-40928 exists.

Affected product: MLEHMANN JSON::XS. 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-2025-40928/ (Markdown: https://insights.sbomify.com/CVE-2025-40928/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40928
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40928
- OSV: https://osv.dev/vulnerability/CVE-2025-40928

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40928/
Summaries are generated and may contain mistakes; the official description above is the record.