Cyber Posture

CVE-2021-47827

HighPublic PoC

Published: 16 January 2026

Published
16 January 2026
Modified
15 April 2026
KEV Added
Patch
CVSS Score 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0001 3.3th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-47827 is a high-severity Improper Validation of Specified Quantity in Input (CWE-1284) vulnerability in Apple (inferred from references). Its CVSS base score is 7.5 (High).

Operationally, ranked at the 3.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

NVD Description

WebSSH for iOS 14.16.10 contains a denial of service vulnerability in the mashREPL tool that allows attackers to crash the application by pasting malformed input. Attackers can trigger the vulnerability by copying a 300-character buffer of repeated 'A' characters into…

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the mashREPL input field, causing the application to crash.

Deeper analysisAI

CVE-2021-47827 is a denial of service vulnerability in the mashREPL tool of WebSSH for iOS version 14.16.10. The issue allows attackers to crash the application by pasting malformed input, such as a 300-character buffer of repeated 'A' characters into the mashREPL input field. It carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and maps to CWE-1284.

The vulnerability can be exploited by any network-accessible attacker requiring low complexity, no privileges, and no user interaction. Exploitation crashes the WebSSH iOS application, resulting in a denial of service with high availability impact but no confidentiality or integrity effects.

Advisories and related resources include the WebSSH app page on the Apple App Store, an exploit proof-of-concept published on Exploit-DB (ID 49883), and a VulnCheck advisory detailing the WebSSH for iOS mashREPL denial of service. No specific patch or mitigation details are outlined in the provided references.

Details

CWE(s)

Affected Products

Apple
inferred from references and description; NVD did not file a CPE for this CVE

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CVE-2026-1092Shared CWE-1284
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CVE-2024-30516Shared CWE-1284
CVE-2024-45351Shared CWE-1284
CVE-2024-55407Shared CWE-1284
CVE-2025-0285Shared CWE-1284
CVE-2025-12664Shared CWE-1284
CVE-2021-47821Shared CWE-1284
CVE-2025-14513Shared CWE-1284

References