---
title: "CVE-2026-63626: Mongoose - Buffer Overflow"
description: "Mongoose < 7.23 contains a buffer overflow caused by improper validation of the IPv6CP length field in ppp_handle_ipv6cp(), letting unauthenticated adjacent peers cause memory corruption or denial of service, exploit requires adjacent PPP or PPPoE link with specific features enabled."
url: https://panop.io/threat-heartbeat/CVE-2026-63626/
---

# CVE-2026-63626 Mongoose - Buffer Overflow

Mongoose < 7.23 contains a buffer overflow caused by improper validation of the IPv6CP length field in ppp\_handle\_ipv6cp(), letting unauthenticated adjacent peers cause memory corruption or denial of service, exploit requires adjacent PPP or PPPoE link with specific features enabled.

CVSS base score 8.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-63626)

## Details

Type

Buffer Overflow

Impact

Denial Of Service, Information Disclosure

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Published

14 October 2026

Updated

15 October 2026

Weakness

[CWE-122](https://cwe.mitre.org/data/definitions/122.html)

## Vendor fix

Update to version 7.23 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-63626](https://nvd.nist.gov/vuln/detail/CVE-2026-63626)
- [https://github.com/cesanta/mongoose/commit/751f14742dea934bec08a507ab1fecc3673d4903](https://github.com/cesanta/mongoose/commit/751f14742dea934bec08a507ab1fecc3673d4903)
- [https://github.com/cesanta/mongoose/releases/tag/7.23](https://github.com/cesanta/mongoose/releases/tag/7.23)
- [https://github.com/cesanta/mongoose/security/advisories/GHSA-pc66-j6r6-49x9](https://github.com/cesanta/mongoose/security/advisories/GHSA-pc66-j6r6-49x9)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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