PuTTY RSA Key Exchange Double Free Vulnerability

Publication date: 2026-05-25

Last updated on: 2026-05-27

Assigner: MITRE

Description

PuTTY 0.72 before 0.84 has a double free in RSA KEX.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-05-25

Last Modified

2026-05-27

Generated

2026-07-06

AI Q&A

2026-05-26

EPSS Evaluated

2026-07-04

NVD

CVE-2026-48850

EUVD

EUVD-2026-31729

Affected Vendors & Products

Vendor	Product	Version / Range
putty	putty	From 0.72 (inc) to 0.84 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-415	The product calls free() twice on the same memory address.

Attack-Flow Graph

Executive Summary

This vulnerability is a double free issue in the RSA key exchange (KEX) component of PuTTY versions 0.72 through 0.83. A double free occurs when a program attempts to free the same memory location twice, which can lead to undefined behavior, including crashes or potential exploitation.

Impact Analysis

The impact of this vulnerability is limited to availability, as indicated by the CVSS score. It can cause a denial of service by crashing the application due to improper memory handling. There is no indication that confidentiality or integrity are affected.

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