Is this vulnerability remotely exploitable over the internet?

Yes. Any Freeciv21 server that is reachable over the network and accepts connections from untrusted clients can be remotely crashed by sending specially crafted packets. Similarly, a client that connects to a malicious or compromised server can be crashed by hostile responses.

Does an attacker need valid credentials or game authentication to exploit this?

No. The vulnerability is reachable without authentication during early connection or packet processing. An attacker does not need to join a game legitimately to trigger the crash.

What is the safest general fix pattern for developers?

The safest pattern is to introduce rigorous input validation and safe memory handling: enforce strict bounds on all packet fields, avoid writing unvalidated data into stack buffers, and use safer buffer-management APIs that make overflows difficult or impossible by design.

Severity:

HIGH RISK

(7.5)

Stack-Based Buffer Overflow (CWE-121) in Freeciv21 Network Packet Handling

CVE-2026-33250

Published:

Mar 23, 2026

Status:

Deferred

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

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May 6, 2026

Vulnerability Type

Category:

Memory Corruption / Buffer Overflow

CWE:

CWE-20;CWE-121

Impact:

Denial of Service via Remote Crash

Severity:

HIGH RISK

(7.5)

CVSS Version:

3.1

Vulnerability Type

Category:

Memory Corruption / Buffer Overflow

CWE:

CWE-20;CWE-121

Impact:

Denial of Service via Remote Crash

Severity:

HIGH RISK

(7.5)

CVSS Version:

3.1

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Stack-Based Buffer Overflow (CWE-121) in Freeciv21 Network Packet Handling

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(8.6)

Server-Side Request Forgery (CWE-918) in OpenClaw Zalo Plugin sendPhoto

HIGH RISK

HIGH

(8.8)

Authorization Bypass (CWE-863) in OpenClaw Matrix Room Control Commands

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

Ship clean & secure code faster

Ship clean & secure code faster

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