CVE-2020-13398Public exploitNetwork attack vector

Client heap overflow via undersized RSA modulus

Published May 22, 2020 · Updated Aug 4, 2024

Heap overflow in FreeRDP before 2.1.1 allows context-dependent attackers to corrupt client memory through a crafted RDP server key. During license encryption, crypto_rsa_common sizes input_reverse from a server-controlled key_length, then copies a fixed 48-byte premaster secret without ensuring sufficient allocation. Exploitation requires a FreeRDP client to process a malicious server's undersized RSA modulus; the overflow can crash the client, and code execution was not demonstrated.

CVSS severity8.3
High
EPSS probability2.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap overflow in FreeRDP before 2.1.1 allows context-dependent attackers to corrupt client memory through a crafted RDP server key. During license encryption, crypto_rsa_common sizes input_reverse from a server-controlled key_length, then copies a fixed 48-byte premaster secret without ensuring sufficient allocation. Exploitation requires a FreeRDP client to process a malicious server's undersized RSA modulus; the overflow can crash the client, and code execution was not demonstrated.

The record

CVE
CVE-2020-13398
Published
May 22, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1203
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. May 22, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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