# CVE-2026-48131: VPND IKE Fragment Reassembly - Heap Out-of-Bounds Write via Sequence Number Zero

> A heap out-of-bounds write in the VPN service allows remote attackers to cause a denial of service by sending malformed IKE fragments.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 May 2026
- **Updated:** 26 May 2026
- **Also known as:** GHSA-4qg4-f998-wjmm

## What is CVE-2026-48131?

CVE-2026-48131 is a high-severity memory corruption vulnerability in checkpoint Quantum Security Gateway, published on 26 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The VPN service may mishandle an unexpected IKE fragment value received on the IKE port 500/UDP during the early stage of a connection attempt. This can cause the service to terminate unexpectedly, resulting in denial of service (temporary disruption of VPN-related functionality).

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

## Which versions are affected by CVE-2026-48131?


## How do I fix CVE-2026-48131?

No fix has been published for CVE-2026-48131 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-48131 being exploited?

There is no known exploitation of CVE-2026-48131 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48131 and fix it if it is affected.

What it is: CVE-2026-48131 is a high-severity memory corruption vulnerability in checkpoint Quantum Security Gateway, published on 26 May 2026. 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-2026-48131 in the wild and no public exploit code.

Affected product: checkpoint Quantum Security Gateway. 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-2026-48131/ (Markdown: https://insights.sbomify.com/CVE-2026-48131/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48131
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48131
- OSV: https://osv.dev/vulnerability/CVE-2026-48131

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48131/
Summaries are generated and may contain mistakes; the official description above is the record.