CVE-2026-43798

Analyzed Analyzed - Analysis Complete

Out-of-Bounds Stack Write in swift-nio-ssh

Publication date: 2026-08-20

Last updated on: 2026-09-03

Assigner: Apple Inc.

Description

A single crafted SSH message gives an unauthenticated network attacker an out-of-bounds stack write of attacker-controlled length and content against any application built on swift-nio-ssh. This vulnerability is addressed in swift-nio-ssh version 0.14.1.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-20

Last Modified

2026-09-03

Generated

2026-09-11

AI Q&A

2026-08-21

EPSS Evaluated

2026-09-09

NVD

CVE-2026-43798

Affected Vendors & Products

Vendor	Product	Version / Range
apple	swiftnio_ssh	to 0.14.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-121	A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

Attack-Flow Graph

Executive Summary

This is a vulnerability in swift-nio-ssh where a single crafted SSH message allows an unauthenticated attacker to perform an out-of-bounds stack write. The attacker can control both the length and content of this write, potentially leading to arbitrary code execution or crashes in applications built on this library.

Detection Guidance

Detecting this vulnerability requires checking if your swift-nio-ssh version is below 0.14.1. Run: swift package show-dependencies --package swift-nio-ssh to check the version. If it's older than 0.14.1, update immediately.

Impact Analysis

If you use applications built on swift-nio-ssh, this vulnerability could allow attackers to execute malicious code on your system or cause denial-of-service conditions. Unpatched systems are at risk of unauthorized access or data breaches.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it is specific to a software library (swift-nio-ssh) and does not involve data breaches or unauthorized access to regulated data.

Mitigation Strategies

Update swift-nio-ssh to version 0.14.1 or later to address the vulnerability. Ensure no applications are running on affected versions.

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