---
id: CVE-2026-121969
title: netrek-client-cow through 3.3.3 Stack Buffer Overflow via handleSMessage
summary: >-
  netrek-client-cow through 3.3.3 contains a stack-based buffer overflow
  vulnerability in handleSMessage() in short.c that allows malicious servers to
  overflow a 100-byte stack buffer by sending oversized SP_S_MESSAGE packets. A
  malicious …
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-121
vendor: quozl
product: netrek-client-cow
affected:
  - netrek-client-cow <= 3.3.3
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T19:27:04.770622Z'
published: '2026-11-04'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T19:27:21.478Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-121969'
references:
  - url: >-
      https://github.com/quozl/netrek-client-cow/commit/fb322e74abee3b0b76a9c5a31df6aab5585d3127
    label: Patch Commit
  - url: 'https://github.com/quozl/netrek-client-cow'
  - url: 'https://github.com/quozl/netrek-client-cow/blob/3.3.3/short.c#L949'
  - url: 'https://github.com/quozl/netrek-client-cow/issues/11'
  - url: >-
      https://www.vulncheck.com/advisories/netrek-client-cow-through-3.3.3-stack-buffer-overflow-via-handlesmessage
    label: >-
      VulnCheck Advisory: netrek-client-cow through 3.3.3 Stack Buffer Overflow
      via handleSMessage
tags:
  - cve.org
epss: 0.00344
epssPercentile: 0.28096
ingestedAt: '2026-11-05T22:38:31.547Z'
---

## Overview

netrek-client-cow through 3.3.3 contains a stack-based buffer overflow vulnerability in handleSMessage() in short.c that allows malicious servers to overflow a 100-byte stack buffer by sending oversized SP_S_MESSAGE packets. A malicious Netrek server or man-in-the-middle on the plaintext TCP connection can send overlong or unterminated message bodies to write server-controlled bytes onto the stack and crash the client.

## Affected

- `netrek-client-cow <= 3.3.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.